In the late 80's, I remember watching games and seeing the OL and DL switching out players constantly. First team to Second team. At times to Third team - on both lines.
The team we have now, and most all of the teams the past 10 years struggled to go from just first to second team. If you watch the Alabama's and other teams with strong OL and DL, you will still see that substitution.
However, looking at the depth chart today, you can see that getting ready to happen at Clemson again. You see younger guys behind the starters getting playing time. Getting experience. Once we get back to substituting, you will see the games lost in the second half stop. They will hold a lead.