Tex-Mex is mostly a creation of restaurateurs of Mexican descent who were living around San Antonio.
Like all food from economically depressed areas that lacked a strong agriculture industry — such as 19th & early 20th-Century Italy — the Mexicans subsisted on whatever could be made to grow or nature made available. So cuisine tends to be highly regional. Food in mountainous Chihuaua is very different from coastal Yucatan.
Same with India. What grows in coastal Goa won’t necessarily grow in Shimla, in the Himalayan foothills.
There is nothing like a nation-wide cuisine, not in Mexico or Italy or India or anywhere else that is environmentally diverse or has been (or remains) heavily culturally or politically fragmented.
There you go, injecting “facts” and “reason” into a thread about food. What are you, some kinda newb?
Food threads feature gluttonous praise, snarling invective, and nothing else. Like this:
“Every one of you addle palated cretins criticizing Mexican food ought to sentenced to six months of eating nothing but frozen, gas station hamburgers, to drive home the point that it is possible to find an unappetizing example of any cuisine, and foolish to condemn the entire cuisine because of it.
See?