Wouldn't it discourage long-time owners from selling, thereby limiting supply and raising prices?
Here's an example currently for sale:https://www.redfin.com/CA/Los-Altos-Hills/27446-Black-Mounta...
They are paying 18.2k.
If it was reassessed today, they'd be paying 40-45k.
If they do what most people who have lived in a home forever do, and are downsizing to something smaller (IE kids grew up, whatever), they will likely end up with either the same or less in taxes they pay now.
So it's not like right now they pay nothing, and they'd pay a ton, it's "they pay a lot, they'd pay more".