Comment by tshaddox

That's an ignorant simplification of how property ownership works. For example, defeasible estates are not a new or rare thing:

https://en.wikipedia.org/wiki/Defeasible_estate

Granting land conditionally such that the ownership reverts once the condition stops being met is very much a thing. I can't find the full details of this particular case, but it sounds like the property went through a long sequences of transfers that probably make the legal situation tricky.