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.