That's rarely the case anywhere. O-lines don't rotate in and out much, might get your QB killed.
That's because so few teams go legitimately more than 7 deep. If you have 8-10 guys that can go in without a drop off then that allows you to get your OL rest like the DL's they face get. To answer the question... yeah, I think when UT had a great rushing attack they had some back ups who gave quality relief.
It is also a good way to prevent injuries to your first OL's.