why in the world would tuberville leave a powerful SEC team to come to an equally powerful SEC team?
Because Tennessee has a top 5 fan base in the nation, has a bigger stadium, more resources, is 8th all time in NCAA, second all time in SEC Championships after Alabama. Historically we are a lot better then Auburn. In recent history we have had greater recruiting classes and more players put in the pros. Auburn is not at the same level as Tennessee, they are not even the top team in their state.
He isn't leaving Auburn.