The comparison with eminent domain is interesting. If the government abolished taxi medallions, are they really taking something from those who own them? The medallion is basically the right to operate a taxi. If the government abolished medallions, then they'd still have the right to operate a taxi, it's just that a lot of other people would too. Obviously they lose a major competitive edge, but strictly speaking, the government hasn't taken any property here.
The best comparison I can think of involving real property would be owning a private tract of land in a valuable area that's almost all owned and unused by the government. One day, the government decides to sell its land. The value of your land plummets. It's still valuable due to whatever intrinsic wealth it has, but the new glut of supply makes it much less valuable. Is the government obligated to compensate you for that loss of value when they sell their land? I'd think not.
The best comparison I can think of involving real property would be owning a private tract of land in a valuable area that's almost all owned and unused by the government. One day, the government decides to sell its land. The value of your land plummets. It's still valuable due to whatever intrinsic wealth it has, but the new glut of supply makes it much less valuable. Is the government obligated to compensate you for that loss of value when they sell their land? I'd think not.