Development raises land value. That's the entire reason it's done, after all. Look at the cost of land in Manhattan vs suburban Atlanta. In the supply-choked cities in the US, development isn't gonna tank the wealth of land-owners, quite the opposite. There are exceptions, but they're "this is the largest available plot in Beverly Hills"-style outliers.

What people want, even in those denser supply-choked cities, is basically just stability. "I don't want to be forced out because a bunch of rich people move in next door, and I don't want it it turn into something dramatically different experience-wise than what I bought."

If everyone in those areas just wanted to maximize the financial side they'd be looking to flip their single family home for a fourplex and put the profit into another, etc etc.

"We don't want this to turn into Manhattan" is NOT what anyone owning land in a maybe-could-turn-into-Manhattan place if they were just interested in the money.

(That's less viable in the middle-of-the-country suburbs because the "increased land value" of the old empty pasture next door could still result in lower land value for your on-the-suburban-fringe neighborhood, if there's high amounts of empty land and more new identical suburbs popping up. But that's not where the problem is most acute, anyway!)