Again, I'm not saying that tau policy couldn't stand major improvements. And I'm not saying that grit and ambition and upbringing and environment don't contribute substantially to individual success (though the imperium earns very few points there.) But that's only half the picture. And saying they're worse than the imperium is, quite bluntly, delusional.
EDIT: Look, how can I explain this. The Tau caste system is not like a Hindu untouchable saying "can I be a doctor?", and getting told, "no you have to sweep the sewers."
It's more like a Vulcan saying "when I grow up, can I be a Klingon?" "No, lil' miss T'Pol, I'm afraid you can't be a Klingon. There might be overlap in the things that you can do well, and maybe, if you're very, very good, you can work together on some projects. But you don't become a Klingon. Now, go study your fourier analysis!"
They'd just find the whole question quaint.