Mkay, let's turn this around then...
I've got a rogue. I know how to be an outlaw, but don't think for a second I'll have any luck playing the other two specs. I have no interest in them, and believe me, I've tried learning them, but they just don't work for me. There is no doubt in my mind that even if the other specs were 25% ahead of Outlaw in sims, I'd stick to Outlaw. Sure, I MIGHT end up doing more dps in the other specs just randomly mashing buttons, but that's more about luck than skill.
Now let's say all 3 rogue specs are within 5% of each other. Let's say Sub wins, Ass at -2% and Outlaw -5%. Which spec, given the above information, do you think I, me personally, would do the most damage in?
I'll help. The answer is what used to be called Combat. Because that is what I'm good at. Playing ANYTHING ELSE would actually "weaken the potential of my team succeeding", to use your own words. It doesn't matter if Sub is better in sims, if I, the player, cannot play like the sims says I should. And because of that, Blizzard cannot force me to pick a spec. They can buff or nerf all they like, but I will always perform better in a spec I CAN play than in a spec that just sims the highest.