Many people in this thread are skeptical about quantum computers, and that's fair. This migration is a big part of my current job, and even I think that there's a non negligible chance that we won't see commercially available quantum computers anytime soon.

The problem is that we're not trying to predict the exact future, we're hedging against possible developments. If there's a 50/50 chance of quantum computers being widely deployed for cryptoanalysis, then there's a 50% chance of this migration being useless. But you don't want to bet your security on a coin toss! So, we migrate.

That's the unfortunate truth of security, sometimes the protections are never triggered. But you still need them.