The facts are straight forward: Playing DPS requires 0 skill and less awareness. I have played many games with lackluster players pushing decent numbers by following someones DPS guide and gear list. The majority of these players are dumb as rocks and really lost their edge when new content was released; because no one was spoon-feeding how to adapt. The sheer exertion it takes to memorize the information, positioning, timing, timers, etc. as a Tank (and occasionally healers) is so high, that it does limit interest. It's a responsibility role at it's core, and I have found myself spending my time online queuing for randoms as I level up to start gearing out and have nearly instant commencements because of it.

In the end, I chose Tank because I wish to drive my game play; and not wait for someone else to consider, possibly somewhere down the line, standing up and taking the same action. You should thank your Tank and Healers because they are sacrificing fun play, so you can enjoy it.