After applying thousands of gallons of paint, and having owned multiple rentals, I suggest it could be that the paint might not have been as bad as any prep work.
I empathize with you in that you likely wanted THIS particular house and part of the deal with any seller is to make a house as attractive as possible for as little cash as possible.
DO you have any legal recourse? IE: Warauntee???
Do you live on an active "fault line"? Forgive that, smile.
What is the age of the house, and do you know the sub surface under the remodel paint job?
Certainly it may have been bargain paint, but I still suspect it was applied over a really poor prep effort.
At this point, to correct the issue, you have a messy,labor intensive task ahead. The cost factor for materials can certainly be less than an entire re-do with new drywall.
One issue you'll encounter IF you attempt sanding the cracking, It may become and extremely depressive, seemingly never ending job.
You might attempt taking some flakes to someone who might analyze the pigments, polymers, and other "vehicles" in the paint? Without a doubt, if it was my mortgage, I'd be on the phone to the Seller, the insurance company, the mortgage holder, an attorney even. I can't know if a "Lemon Law" applies to housing, but I'd be making a lot of phone calls before I ever attempted repairs. I'd also be taking many pictures.
Steven Wolf
(The Rev.)