Yes some of prefer zoning to "mixed" and "diverse" neighborhoods. What's wrong with me not willing to see a laundromat or an office building next to my house? Or what's wrong with me willing to live in quiet family-oriented neighborhood, where I can let children go outside alone since age of 6-7?
If you’re okay with all of that as the price of you getting to live in an eternally quiet neighborhood (that your children will never have a similar opportunity to live in themselves due to zoning-driven real estate prices going far beyond what standard wages can afford), then sure. As long as you acknowledge what consequences your desires have on wider society, then you can say you think the price is worth it or that you don’t really care.
The problem with zoning, is that it isn't voluntary.
Zoning is assigned by democratically elected administrations. HOAs are restrictive covenants that are required for the purchase of a house. Every single thing identified as NIMBYism could be enforced by covenants, and keeping blacks and Jews out was literally their original purpose.
The first zoning law in the country was in Los Angeles in 1908. Part of the law was crafted to force certain businesses to relocate retroactively. It was crafted specifically to target the Chinese businesses, which were the laundromats. White people just did not want to live alongside Chinese people.
Redlining was a further practice of both bankers and zoning having restrictions which were explicitly racially motivated. Levittown, the first planned community in the United States, was very explicitly "not mixed" - it had racial covenants that restricted blacks or jews from moving in. The intent was to sell more homes, as they presumed white people would not want to live in "mixed" areas with neighbors of an undesireable race. That practice continued throughout planned communities and zoning laws all over the country. Many of those racial covenants are still in place today.
As an aside: you can let your children go outside in most cities. The moral panic over children getting kidnapped or abused if they step foot outside the house has been overblown for decades, and at this point is just a bizarre psychological trope of America.
State govts have to appeal to a much wider demographic.
Rich people have the power to change the system but they want to maintain the status quo because they are rich and powerful.
It doesn't seem axiomatic to me that rich people will always exist (I'm not sure I even agree that poor people will always exist, despite believing that the guy who most famously said it was divine), and one of the things I have learned from working in an industry with very rich people is that merely being rich is enough to let you influence the rules of the game. If someone was able to argue for tiered zoning, you can pay people to argue for un-tiered zoning. If there's a law preventing you from influencing local zoning, and you're rich, you can go change that law just as easily as it got created. If there's a law requiring certain representation on zoning boards, you can go lobby that representation. If there's a law moving zoning to an "apolitical" government agency, you can fund candidates willing to politicize it. And so forth.
Making people not have that level of influence/leverage in the first place, hard as it might be, seems like the only viable solution.
Delegation of power to local authority is a central concept of American democracy. Do not throw that baby out with the zoning bathwater.
Because people love zoning! NIMBY is the rallying cry at zoning board hearings, where whiny people who only care about themselves make sure those Chinese people don't put their stinky laundromats near our nice rich white neighborhood. It's the main reason zoning exists! Particularly the wealthy people who have the influence to make it happen, but the casual racists of the past century, and middle class yuppies of the past half century, have plenty to answer for.
But it's also clear that bad zoning (like the 2-stack rule) is also an artifact of poor system maintenance. When you design a system, you may put in certain constraints for safety. Over time the system changes, but the entire design and its constraints are not re-evaluated for each change. So eventually you have constraints that are completely out of whack with the current state. Doesn't matter if it's zoning or a microservice architecture, you're going to end up with crappy legacy rules that only get re-evaluated when things break.