It's been covered, but here's a broader explanation. It does NOT apply to EVERYONE at EVERY airline/carrier, but it's an axion that's held true for a LONG TIME. Pre 9/11, the little 2007-2008 blurb, and now;

ALL hiring is driven by hiring at "the major", or what are commonly referred to as "legacies". However, that DOESN'T IN ANY WAY SHAPE OR FORM MEAN THAT EVERY PILOT wants be hired at a "major"/legacy.

There are jobs that suit guy's needs JUST FINE where they are at, and they are MORE THAN FINE where they're at, and won't leave.

But you will always have "tiers" of carriers, or the proverbial "brass ring".

You will alway have say, a corporate guy that was let go and maybe gave up his number and got the corp gig, and is now BACK in a position interview at a legacy. If he gets hired, his corp job needs a new pilot or pilots to replace him. And all down the line and various avenues. The LCC's used to have this problem in a big way before, it's not nearly as bad now.

A pilot was coming up through the ranks when NOBODY was hiring, yet Southern, Atlas, Kalitta, whomever was hiring so they took a job there. And now, they decided they'd like move on. The legacy hiring created that, which created attrition and said carrier, and created hiring at said carrier.

It's a GREAT JOB, but not a GREAT JOB FOR EVERY ONE. That saying in INCLUSIVE of A LOT of things mind you. Changing personal needs for a schedule, retirement, W2, seniority progression, whatever.

Circles back, ALL HIRING is driven by hiring at "the majors".