I wouldn't go that far. Michigan's pass rush had more than a little to do with it. Texas ran a lot of delayed blitzes and rarely got home, whereas Michigan seemed to regularly collapse the pocket and affect him quite a bit. Not having any rushing threat (Washington ran 20 times for 40 yards) and his WRs dropping multiple passes didn't help, either. That very marginal holding call (many much more blatant ones were let go) when he finally connected with Odunze, when it was still a one-score game, was massive too.
Texas had a weak secondary (every passing game with a pulse put up numbers on them this year) and Penix took advantage. Meatchicken, which rebuilt itself defensively to compete with tOSU and its stable of NFL QBs and WRs, was always going to be a much tougher matchup.