It's not a "nice balance" it is literally the opposite of that.

I believe housing choice is a good thing. The problem is that suburbia almost always takes away housing choice for everyone else.

1. Suburbia is not cost viable.

Notice how suburbs are almost always built around cities and almost never on their own. There is a reason for this; they are heavily subsidized by the city and its infrastructure - eventually killing off the city due to extreme maintenance costs and uncooperative tax base (NIMBYs). This is a parasitic relationship, fullstop.

2. Suburbia is not recyclable.

It is extremely difficult to reuse suburban infrastructure for non-suburban purposes. This effectively eliminates scarce land until a patron spends 10x removing what it costs to install (not happening). This is why suburbs are often just abandoned instead of repurposed (see any rust-belt suburb).

3. Space should not come at the cost of the future.

To navigate suburbia (only viable by car) is to put massive strain on the human body and environment. We were built to walk. If you do not, you will become fat and die (see America). Cars pollute the air to no end, and "third places" can never truly be established - killing communities.

Wanting space is fine, but people should find a way to do it sustainably without harming themselves and everyone around them.

So here's the thing:

The housing that people want is the housing they can afford. Sure, I'd love to live in a 20,000 sqft mansion up in the Pacific Northwest rainforest with a built in pool and free-range dino nuggies dispensers, but I can't afford that, so I live in what I can afford. Problem is, our zoning doesn't permit really anything except unaffordable, bland tracts of McMansions that force you to drive to everything. If you can't afford that, then, oh well, get bulldozered, idiot.

I want to make living in my city affordable; if all my kids can afford is a $400 studio with no car, then that should be an option.

For what it is worth, those suburbs you are describing are decaying in America. Those bars and shops just a few minutes down the road closed a couple generations ago. Many are empty lots or were razed for additional road lanes or gas stations. (In my city: another shooting range for police.) There aren't even sidewalks outside the neighborhood where I live, and this is in an area developed in the 1980s 'shining house on a hill' era of America.

Most people live in the suburbs this guy is questioning, because it's a nice balance of cost, serenity, and convenience.

The cost is blown out of the water, but for serenity and convenience goes: the conveniences are decaying and so the serenity is about all you can hope to get for the cost. More than anything though the spiraling cost destroys that balance. Most renting folks I know can't afford the shops or restaurants anyway because of housing costs. American suburbs are increasingly isolated.