Why is there still so much to do at end game?

[Freakiie]

Yeah everyone needs to play classes they don't like. If everyone level a tank, we wouldn't have this tank shortage.

How to prevent running out of things to do: Do content you don't find enjoyable.

And you'd think people would realise there's something wrong when like 50% of the suggested content is "Hey, why not lvl yet another class?!"