Dallas itself is competing with it's suburbs, Plano/Frisco etc. The development you see was planned 2+ decades ago and really only a surprise to folks that don't keep up (most people, I know, but I tend to keep up with this stuff and like to buy and hold land ahead of development). Bishop Arts for example has been a 3 decade overnight success, similar story with other areas you mentioned. Many of those areas I felt like they took way longer than they should have to get developed, and it's because all money goes north to the burbs. Uptown is about as far south as most money is willing to go. Design District, Deep Ellum, Cedars are proximity plays after Uptown got kind of expensive.
I don't really do much nightlife stuff. But about 10-15 years ago, Uptown was like the young professional/college kid place to be. Many of those folks moved to the burbs after a certain age. But many stayed. Now the prices are high, it seems like it's more full of those same folks that never married, never had kids, etc and just happen to be 10-15 years older. I think it still has the reputation but realistically, younger crowds (<30 or so) don't seem to spend much time there anymore in favor of Deep Ellum, etc.
Anecdotal, but Greater Houston differs from DFW as it's more blue collar and DFW tends to be fairly white collar/corp focused. Ironically, Houston also has much more wealth. So what this means is DFW feels like it IS middle class with some lower, some upper, and a few Mark Cuban's. Houston has a whole neighborhood of Mark Cuban's, you see lower income everywhere, and it's kind of unclear where the middle is. In the exurbs? Is exurb A a middle, upper middle, etc. it's not clear where those lines get drawn. Dallas in particular is more segregated on income (which is correlated with.. you know) with the southern part of town being almost exclusively lower income. Houston is more integrated in this regard, there are pockets of wealthy areas surrounded by lower income areas and the folks interact with each other.
I actually don't hear a ton about the big money buying here in Dallas (Zillow, etc). It's just people that sold their west coast house for $2M+ and move here cash rich. I see a lot of mid-lifers so school district & distance to office is the biggest draw for which areas are seeing the largest price gains.