There are that many 'city image' pretentious people in Dallas? Or any city? Can a city actually be 'pretentious'? They'll always be those kinds of folks, of course, but they're such a tiny percentage of any city they're barely a blip on the day to day radar screen. Oh, you hear about them, maybe, or read something in the paper.
Austin's got quite a few people who like they're 'keep it weird' image, but that doesn't mean that entire group is pretentious about it, it just means they really like that image.
I'm sure Dallas has city image pretentious people. But their % is so tiny, and their impact so small (except for helping to fund some pretty cool places to experience culture - gotta give credit where it is due!), I can't imagine coming home from a day out and saying, "OMG, this is such a pretentious city!"