The American copyright law lets heirs do just that: terminate the transfer of copyright (that is, take the copyright back from the person the author sold it to) if, years later, it turns out that the work was worth a lot more than the author could have dreamed. It's seen as a concession to fairness.
The statute has a lot of fiddly requirements and deadlines for the heirs to meet regarding giving notice that they intend to exercise the right. If they met those requirements -- and it looks as though they did -- then Warner doesn't have a case.
The overarching policy question will be whether Congress will amend the copyright law to extend the term of copyright (again). If they do, then likely it would mean a longer stretch of time between the transfer of copyright and the date when heirs can choose to terminate the transfer. That gives the purchaser more time to make scads of money off the work, say, by making more movies, before the heirs can take it back.
Re: What made Mr Walt Disney so successful (and rich)?
The statute has a lot of fiddly requirements and deadlines for the heirs to meet regarding giving notice that they intend to exercise the right. If they met those requirements -- and it looks as though they did -- then Warner doesn't have a case.
The overarching policy question will be whether Congress will amend the copyright law to extend the term of copyright (again). If they do, then likely it would mean a longer stretch of time between the transfer of copyright and the date when heirs can choose to terminate the transfer. That gives the purchaser more time to make scads of money off the work, say, by making more movies, before the heirs can take it back.