LOL. Dude, that's pretty uncool.
Ok, let's slap things side by side. You've already just admitted that Dark Sun and psionics are pretty much Gnome Effect territory. Like gnomes, they aren't very popular, aren't actually used all that much, but, because there is a really vocal, albeit really small, number of fans, they should be catered to, just like gnome fans.
However, unlike gnome fans, who got, what, a couple of pages in the PHB, you want an entire setting, complete with a new ruleset, new classes, and new mechanics. And, you figure that this is a good idea because a small number of people actually will use any of it?
And the evidence for this is that Dark Sun, according to your own polls, is almost as popular as a couple of other settings, and a totally biased poll where the only question is, "Would you buy this if it was available"? Never minding that you could reword that poll to say ANYTHING and get the exact same results. It's not that 75% of En Worlders would buy Dark Sun, it's that you could get a poll on En World to say that 75% of En Worlders would buy just about anything.
But, I'm the one being totally unreasonable? Your strongest argument is that we should have psionics because... reasons? That has apparently morphed into we should have Dark Sun which needs psionics. Again, because... reasons?
Well, they're about to announce a new series of books in a couple of weeks. Anyone want to bet that it is Dark Sun and/or psionics rules? I mean, if Dark Sun and psionics are such a slam dunk, then you should be confident that we'll see the rules this year, right?
Oh, but, I'm the one being unreasonable.