As already has been said, central planning happens in every city, everywhere, already.
By elected officials and within the confines of the law.
Nothing about that changes, only the direction of the course. Zoning laws, tax incentives, traffic control, just like now but in a different way.
Just like now, but not.
There isn't anything more authoritarian about this concept that it hasn't been before.
When arbitrary decisions are made that likely negatively affect many, but "for the good of the majority" (allegedly) that is authoritarian. Many people have cars. Many need cars and cannot walk a mile or ride a bike. So when you eliminate road transport options you are hurting them. An elderly person can't manage getting a week or two of groceries by train, for example.
That's exactly the idea, within the compound of the city: instead of having distinct shopping districts or malls etc. the daily necessities should be more distributed and decentralized, and smaller districts of the cities being more self-sufficient so that larger movements and traffic are less necessary..
It's forced and the decision-making is not distributed. Arguably this is the most important aspect of a free society--having more decisions made more locally. You want to push them upwards and seemingly without concern about those who don't want it.
And I'd also point out that in the USA, most auto traffic is work commuting. There is no reasonable way to limit living and working in the same "district." Anyone who has bought a house or condo in or near an urbanized area understands that a home is a major investment and that choosing one involves tradeoffs including proximity to work, schools, and necessities like groceries. In many parts of the US people change jobs much more frequently than they change homes. Moving is a PITA. Selling a house is expensive and timing is important. So it is even more likely that home and work will not be in the same "district."
Of course if your central planners also desire no private property and to dictate career moves, then these aren't the concern of Citizen Joe and Jane, right? Having spent time working with a sub-group of one of my employers that was in Daejeon South Korea (and having made several trips there for work) I have been exposed to how that looks, too. It isn't a life I'd choose.
Yes, that includes me as well, eventually I'll move back to a more rural place, same as I grew up. But many people enjoy the city life, or have to be there due to circumstance.
I understand that having lived in dense suburbia because of work and inability to afford to buy a home when I was younger.
Why are you so keen on stagnation?
I'm not keen on stagnation. I'm keen on liberty and decentralized authority as much as is possible. I don't believe so-called experts are the best people to control everything from on high.
We can go back to my first post in this thread, what exactly about a city structure like Houston's is worth upholding to you?
You're constructing a strawman. Just because I don't support your notions of "ideal" re-imagined cities doesn't mean I think all current cities are fine.
Shouldn't a walkable city, with more room for green areas and less car traffic appeal to you based on your prefererences?
I prefer small towns or small cities to megopolis constructs. I think above a certain size many things become unmanageable and unpleasant. I used to enjoy an occasional trip to San Francisco for a day or an evening back when it was much safer and less expensive. Usually we'd drive up, park in a garage for the day and walk everywhere. Sometimes we took BART or CalTrain. But walking a hilly city all day is not for everyone. Mass transit only gets you so far and is slow/inconvenient. It's also gotten expensive, unpleasant, and dangerous.
It wouldn't be outdoor nature obviously, but a whole lot better than the way most cities are now.
Because of the economics of dense urban areas, parks become very expensive to build and maintain.