In the end studies suggest a loyalty program only consist of around 5-10% of a consumers decision which airline to fly. Around 70% is network driven.

The way big airlines operate ff programs these days is as seperate businesses. When UA went into chapter 11 the only profitable part was their ff program. So when they have the opportunity to reduce the value of their outstanding miles it is good business. It is like printing money without significant repercussions, and as long as all airlines do it even better.