When you are deciding where and how to live, the first concern is "how do I sustain myself", and the second is "how do I secure myself". For the peasant that has occupied most of the historical population base for most of history, this is easy. You're on the land because that's where the food is, and if you see the dust from an approaching army, you either run or hide.
For cities this gets more complex. The only reason why cities exist is because they are focal areas for wealth generation via trade and industry. That means a lot of lootable assets, and of course the population concentration itself, which makes for a great source of slaves or ransom. If you hold the city, you're also in a great position to tax or raid the countryside. How do you secure it? Literally the first thing you'd think of is a big, beautiful wall.
But eventually you outgrow the limits of any practical static defense, and static defenses in any case get less useful due to better ways of knocking them down. Just as well - at the same time that walls were deprecated, the Military Revolution was making military forces larger, faster, and more effective. Instead of wrapping your city in a fortress and hoping to withstand a siege, dedicated military installations secured them via power projection. Instead of a city with strong walls, for security you wanted a country with a strong king who could afford a strong army and strong fortresses.
This entire discussion models threats as external - obviously you had to worry about brigands and burglars, even fairly terrifying gangs, but their life expectancy was short. It's not like you would suddenly import an army of criminals to worry about!
Now switch continents, and consider the United States. Left and right should agree that America is and always has been a combination of recursive real estate schemes and a slow motion race war (some times being slower than others). The entire point of the continent was cheap land, enough for you and your heirs out to the tenth generation to each have their own freehold, in stark contrast to the Malthusian struggle of the old world.
If you get the idea that your present government is trying to prevent you from fully exploiting that boundless Western frontier, you might be incited to do something about it, and, lacking funds, you might pay your soldiers and war-financiers via land grants (either directly, or by swapping bonds of dubious quality for virgin land). Freed of the colonial British arrangements with certain Indian tribes, you're free to make further war on them (and vise versa) to open up the continent.
Yet just because the land is available doesn't mean there is no conflict. Besides the obvious case of the Indian tribes, you can model the US Civil War in a large part as a conflict over modes of development for this freshly opened land - would the West be a series of gigantic slave-run latifundia owned by a new aristocracy, or an endless grid of individual Jeffersonian farms and small towns? By the mid 1860s it was clear how this was supposed to go.
Gloss over every manner of swindle around railroad routes and grants, prime Florida swampland, crooked land agents, a hundred massacres and counter massacres, and with a nearly fully exploited frontier the question again becomes one of control - when the wealth of the nation flows through the cities, who takes a cut, who gets the vig, and who gets to bring in their friends? Cities were cheap, historically speaking, but also focal points for physical and human capital. New construction techniques expanded the housing supply, logistical innovations like the automobile made them accessible internally and externally, and industrial enterprises took advantage of this concentration of capital for a massive increase in production.
What happens when something is both cheap and valuable? A bust-out. The civil rights revolution destroyed the American city, liquidating its value and taking a massive cut along the way. In the course of this ethnic cleansing campaign a new urban client class was created - not the upwardly mobile white immigrants of yesteryear, but a permanently supplicant underclass with unshakeable political affiliations.
Where do you move, when the cities are no-go zones and the farms no longer need mass labor? We come to the point - the suburb.
Suburbs are a defensive architecture against an internal threat, the same way that a walled city or a trace italienne fortress is a guard against an external threat. In a dense city, a single signature turns over an apartment block or causes one to be built. The demographics of a neighborhood switch overnight. Not so in an expanse of single-family units, a tiny fraction of which are liable to be on the market at any given point. This slows down transitions immensely - a defense-in-depth, house by house, block by block.
And of course the primary goals of any local suburban planning or zoning board is to secure the existence of the character of the neighborhood and a future for neighborhood property values. That means no concentration of Affordable Housing, and in fact keeping the housing as expensive as possible. The fact that home equity is by far the largest asset of the home-owning class is a self reinforcing incentive to price undesirables out of the neighborhood.
The easiest way to keep things Expensive and Nice is to require a large baked-in cost - large minimum lot sizes, setbacks, driveway, and secondary structure requirements set an effective price floor and encourage building larger houses (no point in dropping 500K on land and 50K on a trailer tiny house). Not coincidentally, these same physical features make it difficult to infiltrate such a neighborhood en masse.
A suburb of exclusively residences with long roads and plentiful open space does not have the same level of ambient noise or noise occlusion you find in cities. Screams and gunshots carry. Music coming from bluetoof speakers carries. A class of scholars laughing with the Faustian joy of freshly acquired knowledge as they wander around to they cousin's house is noticeable.
Those same setbacks and two-story houses end up having excellent sightlines, especially from the upper floor, where one sleeps, whereas the privacy of bushes, trees, and fences mostly obscures ground level views between lots. There are only a couple ways in and out of your average bespoke subdivision, which makes entry by car noticeable, and entry by foot or public transit is made impractical or at least conspicuous by the raw distance involved. The lack of commercial establishments means there is no particular reason to be there anyway.
This all adds up to an excellent solution to the Urban Problem that arose in the 1950s-1970s, in the same way that hill tribes found sanctuary from raiders of the plain. Unfortunately, the historical forces of real estate and ethnic conflict did not stop churning just because one faction arrived at a stopgap solution. The priority of the power structure currently occupying the United States government is to destroy the suburb by recognizing this defensive character and cracking it exactly as one cracks any other defense-in-depth.
Start by introducing weak points on the inside - your neighborhood will be made inclusive, or else. A Problem House will be introduced, along with the entailed ambient security issues. Groups coming and going become more common and less conspicuous, and the suburban desert blooms with nocturnal migratory life.
Then isolate and bypass the strong points - suburbs depend on private car ownership and the ability to get in and out at will for their existence. Increasing the expense of such a luxury and installing "off" switches for entire neighborhoods reduces them to the circumstances of cut-off Japanese islands circa 1944.
Ideally, you would prevent such strong points from forming at all, and break the back of the suburb by banning them as a tactic going forward. Any random quarter-acre in a Good School District is more valuable, even including buying out the structure, when it can become part of the footprint of a five-over-one packed with two-bedroom apartments - thus the housing stock shifts permanently in composition, and your monolithic expanse of imposing ticky tacky shatters into a million pieces.
Recognizing that you're in a fight is the first step to winning, and fortunately, the entire American middle class (and large portions of the upper class) keep so much money in land that they have every incentive to follow through. There is enough combined electoral and lobbying firepower to defeat these efforts if they are recognized for what they are - not for nothing is the National Association of Realtors the largest lobby in DC, and in any random town, the big shots are likely to be some combination of car dealers, real estate developers, and the bankers that finance both. These groups do have a track record of success, once they realize their own interests.
And besides, in an America bereft of frontiers, if the suburb falls there is simply no where else to go.
Yes this is the elephant in the room in so many discussions. The 1960s definitely saw the advent of Anarcho-tyranny in America, where the government did nothing to prevent ethnic cleansing (and probably helped it along), but jumped ugly on any nascent attempts by the population to resist said cleansing. I don't think Realtors are likely allies though, they make tons of money on churn. They make big money when the block is busted, and bigger money selling new subdivisions. They probably wouldn't like the massive fall in property prices that would occur in an outbreak of sanity and a reversion to 1950s norms of law enforcement and tolerance of the resistance to ethnic cleansing.