i agree with obea moore and probably gabe jennings as two good ones from the past 15 years or so.
but in general, i'm not sure that i agree with the other examples of top high school talent that didn't pan out in college or beyond college. there are a number of reasons why some people excel at the high school level and, for many of them, it is not a surprise in retrospect that they showed little, if any, improvement in college or after that.
for example, although i didn't follow granville's career closely, it's not particularly surprising to me that someone with a physically mature body could run his best lifetime effort at 800 meters at age 17 or 18. i don't think it's anywhere near a given that he had the ability to run, say, 1:44 low. at the same time, it is somewhat surprising he wasn't able to more consistently run near the top of the NCAA level in the 800 in college, so perhaps he did slack off a bit, but i don't know.
same thing for people like erin sullivan and julia stamps. they ran well in college, but they weren't world beaters. it's not that uncommon for that to happen to top high school female runners, so i'm not convinced that there was a waste of talent there.
honestly i think the biggest wastes of talents are going to be people that you've barely, or haven't, heard of. the guys who run 25 miles per week and run 1:48; or 50 miles per week and run 13:45-13:55. they don't make a big impression, or any impression, on the national scene and we, nor they, will ever know what could have been.