I wasn’t clear .. I meant hard to find fault with the original quarry and concrete maker who did the job 30 years ago... yes, if anyone recently sold a house (or inspected a house) that had the kind of damage described here without notice to the buyer, I believe they’d have a cause of action.
Just hard to imagine your house crumbling under you, but it DID happen to a friend, here in VA. Shoddy work by a crook. At least it was a vacation home, not their primary homestead. I *think* it was resolved in the courts. But that’s quite different from having your house crumble after 30 years!
I should add, I grew up in a pre-Civil War house ... never had that kind of problem and the place is still standing.