If airlines stopped offering flights then their loyalty programs would not be useful.

Even in this "airlines as point program companies" view of the world, flights don't make money in the same way that electricity going into data centers don't make money. It's a place where you have major costs and you want to try and gamify it, but at the end of the day it's pretty necessary for successful operations!

Consider why airline points even work as a model in the first place! Airlines have blackout dates and don't offer every seat in a plane for points because _they can make money selling a seat for more than what the points are worth to them_.