Sounds about right for any music format on AM. So let's be fair to KXTN on that one. If the station were still on a local FM station, it could be profitable with the right staff and investment. Unfortunately in the dying realm of radio, no major company has that type of patience or is willing to take a risk. Every corporate broadcaster has shareholders to answer to so they'll go with the safest and easiest format they can make money off of.
Tejano was moved to AM instead of just dropping it because there are influential older San Antonians who like and defend the format. But the format was dead as could be.
The station was not profitable, despite loads of perceptual and music research. The listeners were, by then, mostly over 55 and the buyers would not touch it. Nobody could make money in that market with the format just as "Music of Your Life" or 60's Oldies can't make money.
I remember when Tex Mex could be heard in stations across the Southwest. It was all the rage until Regional Mexican formats took over. We have to remember that Tejano peaked around the same time that Mexican migration to the US was exploding. I don't think Tejano died overnight. It just got suffocated out of existence with the Mexican-ification of the American Hispanic demographic.
Tejano never made it in the "Southwest". It was successful in the area within a few hundred miles of San Antonio, and sustainable as far north as Dallas and as far west as Lubbock and Odessa. That's it.
Regional Mexican formats have existed in some form or another since music radio hit Mexico in the mid 50's. XEBS 1410 and XELZ were pure regional in 1964 when I interned in the group that owned "La L-Z" in 1963.
At that time, the format was mostly ranchera in Central Mexico, with a blend of ranchera and norteña in the north. In the US, it was mostly ranchera in CA, NV, AZ and more Norteña in Texas. Then modern banda hit in the earliest 90's and stations started blending. But in Mexico it was never called "regional Mexican". That name is a construct of confused U.S. record retailers who wanted to differentiate between "that Mexican stuff" and José Jose and Julio Iglesias and Camilo Sesto. So they invented in the regional term to create sections in their record departments.
Tejano is an extension of Tex-Mex, a creation of later generation residents of Texas of Mexican heritage and it goes back to the 50's and 60's. Most of the artists are English primary... Selena had to perfect her Spanish to start her career!
But Tejano has never been a broad appeal format outside of markets like Corpus, the Rio Grande Valley, San Antonio, Austin and the like. It started to die when immigration increased in the 80's because none of the immigrants knew the music and the artists.