A couple of thoughts from the Peanut Gallery:
With regionals increasing pay rates, promising a mainline interview or offering an alleged flow through to mainline, it would be interesting to see if they now have an increased number of people applying and coming to class as a result. But, for the data to mean anything definitive, it would have to be filtered to show those who had the quals to have applied BEFORE the latest offerings rather than those just now hitting 1500 (or r-ATP mins where applicable). This would either support or dispel ALPA's contention that the regional "shortage" was a pay shortage rather than a pilot shortage.
Perhaps a fix, if needed, would be moving all affiliated regional pilots into mainline and just be done with it. I don't see any indication this is happening. In fact, quite the contrary. AA wholly-owneds are dangling the flow through as a carrot. And Delta CEO, Ed Bastian, just unequivocally stated he had no intention of moving Endeavor under the mainline umbrella.