Then you bite the bullet send out an email to your customers that you're moving domains and why, rip the band-aid off and move on with your life.

Unless you are hosting an email service and now all your users have to bite the bullet and send out emails to all their contacts, right.

Yep, there is no magic bullet to "thing I rent from someone else who has nigh complete discretion on price decides to price me out." You either regulate (which is what happened here that limits the price hikes to 7% yoy) or figure something out. If you can't leave or retaliate then you're basically proving explicitly why they're able to increase prices to the point of ruining you.

At a certain price you just pony up the $200k to ICANN become your own registrar and then actually own your domains.

The ICANN too can play this game, and ask some outrageous fee every year for your TLD