It's finance and statistics combined. To get a sampling off of the bell curve that is optimal, and preferred, compensation needs to be commensurate. It currently isn't, and pilot who as little a 5 years ago wouldn't even be considered for an interview are being welcomed with open arms, and resultant failure numbers support this this. The options are
#1 increase pay to attract a larger pool of qualified applicants
#2 increase training costs to bring up the skill level of the applicants
available.
When 1# becomes cheaper than 2# pay will increase, and it has, unfortunately for the industry it has only attracted the "dreamers" who ultimately aren't the optimal candidates.
Let's face it this industry isn't for everybody, long hours every day, hotels, poor food and extended time away from family means attracting new qualified candidates is going to become exponentially expensive in pay and work rules. It's getting real.