Two reasons I would suggest.
First NRG does not have a driving ego behind it, like Jerry Jones who has a burning desire to dominate everything.
Second, NRG was not well attended when it hosted the State games a few years ago. Ironically, this is the fault of the DFW and north TX fans who largely failed to make the trip down to Houston. This hurt NRG's profits, and NRG learned a monetary lesson through this. Conversely, the support of Houston (and CenTex) fans who do travel to AT&T yearly supports HS games up there. Funny how it worked out, the fickle, lazy DFW fans might have cost Houston area teams the opportunity to play indoors at home in NRG.
As expected you probably didn’t even watch the testimony to the Louisiana Senate Committee. You ought listen to his testimony you might learn something. Has nothing to do with donations or pillows. The guy is worth $400 million he doesn’t need your donations. He has recovery programs for addicts free of charge to anyone who needs help wether their a Democrat or Republican. Right when I think your post can’t get any dumber you go to another level of dumbness.