The regional business is like a brothel.
You're in a brothel full of hookers (regionals) and a new John (mainline) comes in.
If everyone stuck together, the average price of a "trick" is going to be somewhat higher and all will benefit. But there's a new, younger hooker that's in the room that will do the deed for less and it drives the going rate down for everyone. The new one has low costs because she's younger, lives in an apartment with six other hookers and thinks that she's a 'straight-up baller' because $40K is a lot of money at her stage in life and in comparison to her friends at Subway, she's stacking the cheddar -- even though that $40K used to be a $100K-plus job.
Why would the John pay $X for a dirty deed when he could pay $X-Y for the same?
Eventually the new hooker gets a little older, has a home and a family to support, her costs go up... A few more wrinkles and can't figure out why no one wants to pay a premium even though her costs went up.
Then the brothel adds a new hooker and the process starts all over again.
The newest, and somewhat most egregious hooker is GoJets today. It will be someone else tomorrow and so on and so on until people clue in and get a backbone when it comes to professional aviation.