I think inflationary monetary policy (a good thing) more or less guarantees that in dollar terms (the thing that matters for prop 13) prices will go up every year. I think prop c does allow for some price adjustment for inflation, but it has a crazily low cap
Property taxes can go up 2% per year. That's reasonable from an inflation perspective if you are just living there. (Supposedly inflation has been that low for a long time, but doesn't feel like it in real cost of living)
I mean to the best of my knowledge basically all economists think it is, but beyond that imagine a world where we had stagnation or worse deflation. You would have much less of an incentive to invest money rather than just keep it in the bank.