Yes, Jones is done. That writing was on the wall as soon as it became apparent that a rocket scientist at QB is required to run his offense.
Look at the QBs Tn has gone through: Worley, Peterman, Ferguson (didn't play in a game but obviously saw the problem while recovering from injury) Dormady and finally JG. Only Dobbs has been able to comprehend the offense and run it with some effectiveness.
Dormady against GT was running a simplified version of the offense (don't want to give future opponents tape to work with). There were problems early on with execution but by the second half the TN offense was rolling. Against Fla the game plan was still relatively simple but play calling and execution was the teams downfall. For UMass the game plan got a little more complicated as this was the prelude to GA. Again, execution was a problem but just as Dormady was starting to get a groove going, in came JG. The mood was changed and the offense stalled, but the team hung on to win. Then came GA. Game plan became more complex, players are thinking instead of reacting, timing is off, offense goes nowhere.
Jones said he was going back to fundamentals. If this translates to a game plan the players can comprehend then the team has a shot to win. But if the game plan is similiar in complexity to GA then we will see more "deer in the headlights".
Unfortunately, there are few rocket scientists playing QB, therefore Jones will have great difficulty in finding another Dobbs to run his offense!