Strong evidence (FAA stats etc.) support the notion there are about twice as many active ATPs in the United States as there are jobs flying at the regional airlines. That number does not even include those who dropped out of flying and went to other fields because the pay was so awful or the lifestyle was not suitable. America has long been a favorable location for cheap pilot training with literally hundreds of thousands of people holding ATPs at any one time, with well over a hundred thousand (around 140k I think) considered currently active by the FAA.

No pilot shortage currently exists- only a minor shortage of those who are willing to do the job in a state of poverty. If the regionals bring pilot pay on par with most other jobs of comparable training in the world, instantly the alleged shortage will be gone. First year pay is typically well over $50k for similar jobs like engineers, accountants, paralegals, nurses etc.