There's a fairly good solution. Start charging everyone the same tax, but the amount they pay will follow the old prop 13 rules. The rest will be a special lein against the property. You may optionally pay down the lein, or simply wait until the property is sold, when the lein is settled from the profits. Then add in some exceptions for the value going down, and maybe a reduction if the extra is paid early.

Then you won't have people hold on to inventory just for the taxes, and eventually things will even out as people sell each year.