When you found out the builders did that, what you should have done is stopped the work and have them correct their mistake on their own dime. This is an unforgivable mistake and a team of professional should never make something like that.
Obviously I am not in your shoes, but this is insane to me. Any supervisor or consultant or surveyor visiting the site should've caught that.
My wife and I concluded that we got what we paid for, and you're right that in hindsight we should have taken legal action against the contractor. I don't know how breaking down the whole exterior of a house to fix it down to the foundation would feel though. At some point we thought of selling the partially completed structure.
Not your problem.
Also, a lot of people who build a house do not live in them for a very long time. In fact, there is no data to show they live with them for longer than people who buy existing homes.
I am certain that if you went through this, you would find it to be a very large problem.
The foundation would be a pain in the ass but ultimately, as others have stated, that's kind of not your problem.
I had a landscaper screw up just about everything they could building a retaining wall, and they couldn't even get me an extra bag of grass seed after the fact.
The bathrooms have slightly smaller tubs, though we scratched one of the larger tubs while trying to fit it in, and the supplier wouldn't accept it. It's still in our garage lol.
We were building on a contract where we paid for material at cost, and the contractor made their fee on the labour. They were inexperienced, I'd obviously never use them nor recommend them. We made them pay for most of the damages that we could quantify, and for things like crooked walls/non-90° corners we couldn't really do much.
To an untrained eye, the house is not bad, but we know where all the mistakes are.
I also had measurements issues and a contractor that tried to force it to me. I just said I will not pay until it's fixed. The next week everything was fixed.