I didn't watch the end of the game but generally in a blowout backup players come out at the end. They are playing in the National Championship game, so I would expect them to give their best effort because for a lot of them this game will be the pinnacle of their football career.
In this game, I heard that the backups for Ohio State were rotated in throughout the game, more than usual anyway. It was part of the game plan, so that the first string players could catch regular breaks. I think that plan worked out pretty well for the Buckeyes. There was very little drop off in play.