Heck, you gotta admit each regional style is "genuine" to the locals. It's easy to break the styles out as represented by their locally-based chains. Cal-Mex has El Torito, Taco Bell and Del Taco as its representatives; AZ-Mex has Macayo's, Garcia's and Any-berto's; and Tex-Mex has On The Border and Pancho's.
Texas is also home to Chili's, Macaroni Grill, Olive Garden, Red Lobster, Pizza Hut, T.G.I.Friday's, 7-Eleven, Whataburger, Bennigan's, Cici's, Chuck E. Cheese, Tony Roma's, Fuddrucker's, Schlotzky's and more.
New Mexico has no big chains, but distinctively good food. We thank them for that...and for separating us from Texas.