I get your point, but every time we wanted to see the backup, we were correct. All of those starters were busts. They were not the future. There was always the possibility that one of those backups could have been the future. They all happened to be just as bad as the guy they replaced.
Of course the odds of the backup being a franchise QB are higher if he's a high draft choice, but no sense in sticking with someone who isn't the future. These facts don't mean that trying something new is a bad idea. I don't understand what people are saying when they make your point. Are you saying if we stuck with one of those starters that we'd have a franchise QB now? I think not, and TT isn't a franchise QB either. We might as well see what we have. If it's a complete failure, great, we'll get a better draft pick.