The problem is the lack of business-reason to spend money on things that do not raise the property value. Unfortunately “fixing things” usually carries a negative value return.

The common things flippers do (and I know this from some friends who did real-estate for flippers) is buy houses that mostly need the most efficient changes - new tile, paint, etc, with minimal inexpensive fixes to make the house saleable. And honestly, that’s obvious when you say it. The extension of that is that if you can cover up an issue or the issue is not outside margins of being saleable (old septic, safe-but-near-EOL electrical, less ideal insulation, intentionally avoiding discovering asbestos where it probably exists, etc), you should.

Then, depending on local laws, flippers have more limited disclosure requirements than builders. Which means anything that isn’t “gross negligence” that cannot show up on a home inspection… you. just. don’t. do.

Here’s an interesting article on the risk.