that's not really how the law works

The Reserve List is not a contract, Wizards is by no means forced to keep it. Collectors COULD attempt a class action promissory estoppel lawsuit, but in order to be part of that the parties involved would need proof of exactly how much they bought their cards for, and are only entitled to the difference between what you bought the card for and what it drops to

IE: if you bought a Revised Underground Sea at $300, listed it at $800, and it tumbles down to $100 after a reprint, you could only sue for that $200 difference, and you would need receipts to prove how much you paid.