Mazzy
There are always the two types of flying instructor at most schools - the ones who are hour building and the ones like yourself who are doing it for the love of it.
There are two sides to everything and indeed just because someone wants to go on to an airline career it does not necessarily make them a bad instructor. I met two of the best instructors during my training and they were both from this stable.
What I would say is that the career instructors tend to be the ones who provide the continuity at a school and it could be argued that they eventually do become better instructors due to their vast instructing experience. I know that is a mass generalisation, as they can get set in their ways just as much, but I think if you are doing it for the pure love of it then that must be reflected in your attitude and instructional style.
So with that in mind I think you are going to have your cake and eat it! Instruct for the love of it, and earn a decent wage which will allow the lifestyle choices that you (probably) want to make from IT.
I think the majority of posters in the 'Wannabes' forums (fora?) are by definition wannabe airline pilots, hence why they tend to view instructing as a way of keeping current and building hours after qualification. Perhaps the view might be slightly different in the Flying Instructors and Examiners forum?
I wish you well with your choices.
PP