Hotel inventory in the CBD has been below 'should be' anticipated levels for decades thanks to a nice string of events, some common across the country, some unique to The Metroplex:
-Like most growing Sunbelt populations centers, White Flight suburb building destabilized the central city sending much of hotel inventory growth toward the edge of town. New & improved schools in the new & improved neighborhood got all the attention and resources, up to date abundant highway access, preferred retail destinations, new office buildings...
-DFW Airport is very much in the ~middle of the population center greatly increasing the convenience of a near-airport hotel location. Even with the rise of Collin County, the big airport is still roughly central and convenient for area residents and over-night visitors. There's always a hefty collection of hotels near a big airport, but in DFW the concentration has been advanced by an airport location convenient to business centers, shopping destinations, entertainment/tourist venues and residents.
-The recessions of 1980s was wild enough for everyone, but in the Fossil Fuel economy of Texas crashed hard and made everything worse. Dallas, specifically the CBD, was double-D devastated thanks to the crony-conoclastic S&L and Real Estate meltdown. I believe most of the white collar criminals never got investigated, few were punished. But the city suffered in deep freeze because of it, sending whatever moxie was left toward the edge of town.
-Despite all of this, the CBD/greater downtown comprised the biggest employment center, but the allure of suburban newness usurped overnight stay desirability. The convention center has always been popular, but for a decade or so the regional dynamics created unhealthy relationship as CBD hotels became overly responsive to Convention Center activities decreasing variety of hotel type.
All of this contributed to a downtown hotel room inventory about a quarter of what would be typical. Since 2010, hotel inventory has increased in the downtown area, and the type of rooms available have expanded; the increase hasn't really kept up with the neighborhood, though -- we're just now beginning to see the return of venue variety. Expect to seem many more hotels, and a huge increase in variety and style.