I'm certain that any large scale ab initio program would be structured like this...

You take out a loan for training. The company makes the payments as long as you're in good standing. Good standing will be pretty much anything the company says it is. Including X years of service, with Y years as PIC.

You can walk away at any time, you just have to start making payments.

You can't sue the airline and say "well I decided I wanted to be home more with my dog, grow my beard out, and open a coffee shop but I want them to keep paying off my flight training loan".

There is a big difference between "training contract" and "employer-sponsored vocational training/certification".