Where have you heard they're adding football? Please link a link or tweet from a credible source.
UTEP is not keeping out NMSU. NMSU is not in CUSA because their football program was awful, still don't draw, and share the same TV market as UTEP. What is any conference gaining by adding NMSU, when they already have UTEP?
I agree that the games would mean more and you could make it the last game of the season, and schedule different teams out of conference. That doesn't mean that CUSA should add them. Why would ODU and the Floridas want to add another team further out?
UTEP and NMSU are not USC and UCLA and El Paso is not Los Angeles.