Suggestion: Every owner sets their own property "value". That value is also the price at which they are legally required to sell if offered.
It sounds rife for yucks. Imagine making a megarich person mad online and they buy your house out from under you. So you move to another one. They do it again, and again, putting you in the delightful position of playing chicken with their vindictiveness and your ability to pay your own property taxes.
Moving is colossally inconvenient, and extra horrible when you're forced to do it.
Can't imagine local supermarkets being able to endure the inevitable bidding war on their properties from walmarazon.