I have never understood the thought that playing games in certain areas of the country will lead to increased recruiting in that area. I know lots of coaches that believe it, so I''m sure I'm in the minority, but I don't see it .
This isn't the 1980's. Almost every recruit has a TV at their house with 3 different ESPN's, all the networks, etc. The kids know these big "name" games are being played no matter where they are. I don't think some kid in Atlanta got any more excited about the Clemson-Alabama game than some kid in Texas just because it was being played there.
They only reason it could be beneficial that I see is that they could go to the game on an unofficial visit a lot easier than they could travel to one farther away.
I agree with War Eagle on how it helps. But I also agree that Alabama and Clemson didn't help themselves in the Atlanta area by playing in the Georgia Dome. But part of that is because Alabama and Clemson are already Atlanta-area programs by proximity.
Alabama playing in Dallas is putting themselves in the local news in a market in which they aren't typically a topic. There will be local (and national) advertising for weeks leading up to that game. I'm sure Saban will make sure lots of local coaches and players are there. It's just a good idea to go into an off-the-beaten-path market like Dallas and throw your name and brand around.
Notre Dame played here in San Antonio in 2009. It was on bill boards, on radio talk shows, in the local news, etc. They held a big pep-rally downtown near the Alamo Dome, etc. People (including HS players) from all over drove in to check it out.
Anyway, I agree with your assertion about programs being more nationally known these days than 20+ years ago. But being able to see a game on ESPN or look something up on the internet is still no substitute for physically rolling your program in to town for a big-time, Cowboy Stadium game.