Someone who’s in their 20s or 30s can easily make some big salary increases while their career path is still in its earlier stages. Those are personal trajectories that help them catch up with their more established peers. A sales rep having a good year can have those kinds of increases.
When those careers start stabilizing and the promotions are slower in coming their prospects for salary increases are more closely tied to the fortunes of their company and their industry. I know of no industry whose fortunes are increasing to the tune of 30% in the next couple years.
If 70% of all mortgages involve these exotic loans, what percentage of those buyers are still in the earlier stages of their careers? It can’t be anywhere close to half of them. Bear in mind, it probably doesn’t even take 5% of all recent buyers suffering a foreclosure or short sale to cause the entire pricing structure to collapse. All the action occurs on the margins.