I wanted to build a duplex but "zoning laws" say that wasn't allowed, only single family detached houses with at least X amount of land.

Most zoning laws are serious bullshit and work as defacto segregation to keep the dirty ~~brown~~ poor people away from the nice good rich folk. It's why suburban school is a totally different things from poor urban school.

Zoning laws are why developers in LA can't afford to build anything other than luxury condos. Land is literally too expensive to build. As an example: a requirement to have at least X parking spots per X units, even when it's built right next to a metro and a bus depot and you're building low income housing for people who are less likely to own cars in the first place.

Too many NIBYs whining about things.