As an OO guy, those numbers that Chip is magically pulling out of his hat are completely fabricated. One must ask why Chip alleges that 18000 pilots will be needed in three years instead of thirty. It's because he knows that in the next several years his company will not be able to keep the 4200 pilots that he has on property now and that his regional will shrink to a sad shadow of what it is today. So he has naught to lose by approaching Congress and spinning the numbers in the hopes that some ignorant Congresspersons cast their vote in support of the RAA executives. If minimum flight experience requirements change for an airline pilot from 1000/1500 to 250 hours wet commercial, all the regionals will be able to start paying $22 per hour and even more people will flood the market.
I think that the ultimate answer to your inquirty, OP, is that there would not now be regionals or regionals will soon be going out of business owing to a dearth of pilots if there were not enough pilots. Apparently, they are still afloat, because even though some of them are putting in unprecedented efforts at recruiting, none are about to become defunct any time soon.