We didn't put that game away until the 4th and Rosier played a pretty solid game overall. Yes, his completion percent was still down but he ran the ball well and has some good throws when we really needed him to have good throws.
Perry had no chance to throw the ball. There was no reason to have him throw when he came in. He also fumbled a snap which doesn't help his cause to get real snaps unfortunately.
I get it, Perry or Williams are the future but Rosier gives us the best chance to win right now. It is what it is. Until he is downright dreadful, they aren't getting in. History has shown that time will come at some point. Just be patient.