You're replying to someone that specifically mentioned pollution as a reason to keep certain uses in different zones. Did they edit their comment?

Extreme examples. In reality you’ll see more service industry like bodega, accounting, cafe, etc

If it were possible, it would produce far better outcomes than what we are currently seeing in SF. No chicken farmer or tanner could afford to build in SF, so that’s not much of a concern. And it would mean a far more diverse housing supply than what we currently have.

Even without zoning, it doesn't make economic sense to start a farm in a residential area.

None of those things are economically viable to put in an area that can support residential housing even at the single family level of density.

The only way they get there is when housing is built up around them.

If you're too lazy to fire up Google maps before you buy well then that's on you.

Having local restaurants and small businesses in walking distance instead of international mega corps in driving distance sounds horrible too.

Yeah, but being allowed to have a couple chickens on your small plot is an example of allowing sustainable and relatively poor living. Can't have that! We want you supporting your local supermarket instead! The one that delivered that egg from that licensed farm 200km away in the middle of nowhere.