Zoning laws aren't laws of physics. People make those up to align with what works best for them. Prop 13 strongly incentivizes less housing (because it boosts voters asset values with no downside to homeowners) and more commercial (because cities now rely on sales taxes to stay functional).

Until the landowners start to feel some downside from the housing disaster don't expect anything to change.

Landowners are a minority in the city. The divide is deeper than just property values because 100% BMR units are obstructed the same way.

if landowners are a minority of the city, then how do laws pass that benefit them so much at the cost of the majority?

Look at this year's no on 15 campaign. If you lie, but lie loud enough, even people who are hurt by your tax cut will support it.