So why wouldn't developers simply build higher-density housing to maximize this crazy profit per square foot? Why not buy your single-family home, demolish it,

So why wouldn't developers simply build higher-density housing to maximize this crazy profit per square foot? Why not buy your single-family home, demolish it, and build a multi-family/multi-storey apartment building and maximize the profit from that high-value land? Do they hate money? ... or are there regulatory barriers preventing them from doing that - barriers that are supported by existing property owners, who like their house prices tripling every 7 years. It must be that they hate money.