Fortunately, there are already not enough foreign pilots so I doubt the work visa idea would pan out. Unless US airlines establish paid training programs in third-world countries to generate low-cost seat-meat. But there too many political, security, and public perception issues for something like that to work.

If it really gets bad, airlines will have to start paying for ab-initio training. That might not be all bad...

1. A paid ab-initio program would attract better applicants, who will have more options in life than some mediocre kid with $150K debt and an ERAU flight ops degree. This will help keep compensation reasonable, or they won't be able to retain those people.

2. The airlines would probably want the ab-initio folks to start in the feeders, but regionals can't afford to pay for ab-initio. Majors would have to pay for, and the pilots would then flow through the regionals and eventually up to mainline. This would get effectively integrate feeder/major seniority lists. Might but the regionals out of business in the long term but maybe not.

The 1500 hour rule will not hold up under a serious shortage, I'm certain an exception would be made for a 121 ab-initio program. The students could get some post-CPL experience working as CFI's in the ab-initio program, teaching those who come behind them.