There is no way to know if Stegen would've been as good as Bravo in the League, the only thing we know is that Bravo has been sensational for us. It is not Bravo's fault that Stegen got injured and he got a better start. Stegen was unlucky that he got injured before the season started and that Bravo took his chance and made the most out of it. I still fail to see Bravo's fault in all of this, what did he do wrong? If he did nothing wrong and people still want him benched, that's a problem with the Barca fans right there.
It's not about if he did something wrong or not. ter Stegen is not an inferior keeper by any means but he's far younger and has a higher ceiling. It's not that we want to see him benched, it's that we want to see our long term future taken care of more than we care about appeasing a single player out of the interest of fairness. ter Stegen was signed because he is a very talented keeper who is very young, and he could be in between our posts for the next 10-15 years, improving all along the way. Bravo only has a couple seasons left of his current level, and that current level isn't something ter Stegen can't match in his current state.
If anything Bravo should be happy we plucked him from a career of mediocrity and allowed him the opportunity to have the best season of his life here. Him becoming backup is a necessary step in the right direction and when we're talking about "Fairness" I don't think it's fair at all for ter Stegen to have been courted for nearly two years, given the #1 jersey, and promptly benched because Alex Song couldn't control himself in training. If stegen stays on the bench for yet another season despite being a CL and Copa winning keeper do you see him being happy with that, or do you see him jumping ship to one of the numerous clubs foaming at the mouth to sign a keeper of his quality who wants more playing time? Mats isn't La Masia, so we have no reason whatsoever to expect stupidly blind loyalty from him the way many do with Bartra. If ter Stegen leaves (A lot of people here were talking about sending him out on LOAN! Ha!) and we're stuck with Bravo what do we do when Bravo declines? One step forward, two steps back. If Bravo decides he doesn't like becoming backup he can leave. There are plenty of 30+ year old keepers willing to play backup for the best club in the world, and even if there isn't, Masip can play backup and I'm sure he'd do a good job if given more than one game a season.