Why building codes exist.

I was recently looking at a home near Jackson Hole Wyoming where my parents live. This home was built 30 yrs ago without (i still don’t think there are) building inspectors that regulated construction in any way. The foundation on this home was barely 6″ in the ground, not the typical 30-36″ deep for frost depth. As a result the heavy winters have taken their toll on the foundation and a large section is all cracked, falling apart and causing the home to settle. If they had poured the foundation properly the first time, it would probably be in great condition today. Unfortunately, now the home needs to be jacked up, foundation cut out and replaced with a new wall. Kind of a pain to do and probably expensive to the owner. In my opinion it would probably be best to replace the entire foundation but the cost to do so would probably be prohibitive. Anyone ever done this before?