I would suspect the vast majority of the cost of drugs is R&D, including the FDA approval process. They can factor that in on initial cost when they release the drug. The 10% is only for increases.

Hopefully instead of someone buying a drug that has already been released won't buy it because they can jack up the price 5000%. They would have to factor in the 10% rule when purchasing. Unfortunately this might lead to expensive release costs, but that already happens.

It might not be perfect, but 6000% increases because more yachts is a hell of a lot worse.