You’re really, really right. Yeshivos have always wanted the intelligent, personable boys, and when the plight of OTD or nearly-OTD boys came to light, a plethora of yeshivos opened up for them. Now, all those boys without a head exploding with brains and lots of spunk, but also without OTD tendencies, are left out in the cold.
My cousin had nearly the same problem, except that he actually was smart, but there were so many geniuses in his grade that compared to them, he looked average, leading many yeshivos in the area to think he wasn’t qualified. He ended up going out of town.
The problem is that yeshivos don’t want it to be known that they’re catering to “sug beit” boys. Of course, having a top-tier yeshiva is great, and having a yeshiva for OTD boys makes you feel good about yourself, but the boys in the middle? They’ll contaminate by sug alef yeshiva!
Girls are lucky (?) enough not to have the problem in the same way— for them, it’s more of a “how rich/frum is your father?” thing.