Hypothetically, let's say I owned a modest home. Then, what if a very wealthy person who grew up in that home wanted to buy it for a grand sum of money? In that case, I'd be torn between revaluing my house to a huge amount (that no one except this one person would be willing to pay) and being forced to sell. It's an interesting scenario, because that wealthy person could lower their valuation almost immediately after the sale, since no one else would pay what they paid.