Actually, I know much more about Michigan running than Texas, but Texas does seem to have a penchant of having a few decent HSers that don't do much later.
As far as Gomez, you are right, he was no world beater. He did run 9:07 I believe a few years before the Hauser bros were running similar times. Gomez (who reportedly ran 35m/week) followed up his 9:07 with ... nothing. The Hausers did a little better (understatement for effect).
Thanks for catching my Sheppard error... my mistake. I had intended to mention Eric Henry (not Sheppard) who ran in Houston I believe an 8:51. I believe he still runs, and if I am not mistaken, ran a 19:30 5K a coupla months ago.
Last I heard from Angel was that he was competing for Azuza Pacific in the mid-90s. I do believe he improved marginally from his HS times, but I threw him in anyway.
In my opinion, if everyone knows who these guys are (Brantly, etc.) and they have been running a number of years, then I am not sure I can say they are the right fit for "Big Potential / Short Career" topic. HSers though who run pretty fast, but then don't follow it up seem to fit the description to me... Big Potential / Short Career.