Root cause? Simple. Airlines are businesses that are there to make money. Pilots take a huge amount of money out of the business. Pay pilots less, make more money. Repeat until broke and/or major accident occurs. It's so easy an idiot could have thought of it!
For what it's worth, I know a couple of JQ JFOs. Compared to their contemps of a similar age they are all pretty happy to be where they are rather than flying 50 year old Cessnas around the desert, especially considering that the boys and girls doing that are by and large all in a similar FEE-HELP debt position (actually a little worse off as they aren't making enough money to pay off any of it).