What do you guys think is the cause of severe lack of Tank users?

[Lyth]

...

This is called equivocation. You've said the same thing that I have, except that you've re-defined "enmity" to be both "the numerical value that the AI uses to determine who to attack" as well as "the threat of retaliation that deters a human player from entering your zone of control".

By the way, you could just as easily have used overpower to pick up those adds, back in the day. Holding a GCD just for the sake of sitting on the right step of your combo was a dps loss.

It's not about the number of buttons you press, but rather about the number of decisions you make. Play smart.