BiS is irrelevant in a game where the next expansions gear outstrips what took you weeks to obtain. The content is what's worth it. Unfortunately, and it's like this in every game, players want to optimize everything and meta all the fun out of it. So people chase BiS instead of playing the game. And unfortunately there's not many games that can facilitate this without player gatekeeping. Hence, the need for BiS.

I just wish we had a better system, but here we are.