> Not confused on that. My point is that the guy paying 2x rent than his predecessor in the unit — rents can rise freely on vacancy under Costa Hawkins, so rent control doesn't play into this as you point out — is not contributing one extra dime in property tax, since the property tax on the building hasn't changed.

The property tax will change each year as the assessed value can change year to year (but only, absent a change of ownership, increase no more than 1%/year.) The only time it won't change is if the assessed value doesn't change.