I think the OP has some valid points. However, I cannot see the value in the "never again" position taken up.
It is nice to try other airlines, when they fly where you want to go, at a price that is reasonable, and at a time that suits. I really liked CX to and from HKG in J. But that is because I wanted to go to HKG. And they had a deal with an agent........VS is good in Upper, but it doesn't quite have all the routes we want....
We are a bit more "stuck" with BA as we live 20/25 mins from T5. So we would not adopt a "never again" perspective.