I'm not the most appropriate to expand that, but public key cryptography isn't a one-way function. It can be reversed, it's just currently infeasible. Within the next 5 years, it may not be that hard, but I highly doubt about it. The whole situation involves quantum computers, which I'm completely unfamiliar with. Not sure if it requires a hard fork, the wallets could simply be programmed to not send money to addresses that have already revealed their public key. Otherwise, we could fork it and change to a quantum resistant algorithm.