Just because a coach has "done this for years' doesn't mean it is the right thing to do, or the effective thing to do to take the program to the next level.
IMHO, Barnes likely has gone as far as he can go at Tennessee. Firing him. or allowing his contract to run, without a replacement lined up would be a disaster, so I in no way want to change at this time. However, I would be planning his succession. if I were Danny White I'd be blocking the plan out and starting the process.
Since we are Tennessee, however, we will wait until Barnes has cratered, undoing all of the excellent progress he has made since 2017-2018 to this year before we do anything, handing the new coach a mess, and likely a huge severance package to Barnes.