When dps start doing 2x or 3x of a tank the tank maximizing damage doesn't matter in the slightest.

It will be the tanks job to survive Busters and spam aggro combo.

Right now a tank maximizing is very noticeable because we're only 30 percent behind and its a good spot to be in. Eventually dps will be doing 6 to 8k dps each and tanks will still be sitting at 3k. Suddenly the diff between a top 10 tank and a middle of the road one is smaller and smaller as time passes until you can get 1 percent more damage by having said top 10 play tank or 10 percent more raid damage by having same player play a dps.

You start to put your worst players in the tank role because learning CDs and standing where they're told to stand is easy

All of this gets worse the more time passes that we only increase in output at a fraction of the rate a dps does.