There's never been one cause there's never been a swath of baby boomers getting ready to retire. There's never been an ATP required by law (not just economics)to get a job at a regional, the duty regs have never changed, our industry has never been more volatile.... etc etc

There are a lot of new factors going on right now that have "never been", so i really wouldn't be too surprised if we do see one. It's not just the flight schools that are predicting one, most aviation "experts" agree...so I have a hard time discrediting that just cause it has "never been".