They can't force you to sell, you have the option of just updating the declared value to the new market price.
But I brought this up initially in the context of patents because I don't think this would actually be a practical or politically palatable way to handle property taxes on owner-occupied housing. But when we're talking about intangible corporate assets like patents most of these problems go away (IMO).
This isn't implicationless. What if you can't afford the taxes on the newly declared price?
A whale could conceivably force people out by offering a price above their ability to afford the taxes. If they don't sell, they get evicted due to tax nonpayment. If they do sell, they get the money but now need to find a new place to live in an appreciated market. Their autonomy is removed by force.
Under the proposal, lucrative offers can still lure buyers into selling, but the security of private property is removed. You have to live under constant threat of a whale, e.g. Blackrock, swooping in and offering marginally above (market + e), forcing you to sell.
But you still need somewhere to live. And now you have (market + e) dollars, but the market just got redefined by Blackrock and you cannot afford to buy your neighbors house because it is now priced at (market2 + e) where market < market2.
Blackrock does this sequentially and can manage to legally steal private property from entire cities, just because they had more starting capital.