I wonder how many of the non business properties are still under Prop 13? I can't imagine it would be that many at this point. Business property can probably be held in some sort of trust so it appears to never have changed hands over the years.

A huge number of residential properties are receiving massive prop 13 subsidies. Open up https://www.taxfairnessproject.org/map and go poke around a random neighborhood in Palo Alto. Blue means the assessed valuation is close to the market price, while red means the assessed valuation is a tiny fraction of the market price.

Lots. You can inherit prop 13 rates from your parents or grandparents.

It’s a completely sick system that is literally creating a landed gentry