Great post, especially the second paragraph. It's basically impossible to change your team. It's all the memories of your youth and being with your parents that keep you going back, like a sense of nostalgia.
If St Johnstone were to go tits up, I couldn't move onto a new club, because I'd always remember things like my Dad taking me to it first as a family day out, watching us put three past Monaco, and thinking Nick Dasovic was the greatest player ever.
You might have some good times supporting a new team, and get rid of the shysters, but you'd always hark back. Kinda like a lost love I suppose. Something on a true football fan would understand.