Prop 13 actually did save a lot of homeowners. In places like San Francsico the assessor was pushing up values at way more than the inflation rate of anybody's income other than the 1%, forcing sales and people having to move away - and homelessness though that was a lot less visible in those days. City loved it - could keep the tax rate low but bring in buckets more money every year. Prop 13 put a kibosh on that, causing major cuts in local government jobs and activity. So on one hand it saved a lot of people from being pushed out on the street, but cut the funding for a lot of things (including schools, initially) that needed it.

Another thing it did was make the tax increases predictable. You buy a place, it's reassessed at what you pay for it. Then, the tax rates are relatively fixed (1% of value plus what's voted for plus "fees" that are on the tax bill but not related to the value of the property) and the assessed value increases at a low inflation rate. Places that have a lot of turnover in the real estate market get increased local tax revenue; places without it don't. So there definitely is a rich vs poor thing going on, leading to a lot of funny things with sales taxes and various state-level bennies. And schools that are pretty much entirely state-funded now. And commercial property that almost never gets reassessed because the transactions are carefully structured to avoid that so the property tax take has shifted from mostly commercial when Prop 13 was passed to mostly residential now. All of which *could* have been predicted at the time but none of which was. Oh well...

And yes, it did save a lot of middle class people from bankruptcy and homelessness. But it saved the top earners and capitalists a lot more. On balance it was probably a good thing, but the consequences are still working their way out.