In my "crowd" growing up, there was this PG boy who liked to take apart things, radios, whatever to see how they worked. In hindsight he seems like many (most) of the PG kids described here, selfmotivated to learn, and like sitting down to task. he teaches math in some university in Ohio.
On the other side, my closest friend from earliest age, wasn't into playing chess, we played Bobby Sherman songs loud, over and over, and sang. She got into marching band and competitions and did musical theatre. I bet that many people didn't think of her as seriously PG. She got the highest score ever in undergrad physics studies in our university which is 150 year old and a very big school. She went right into a PhD program in nuclear engineering and got offered classifed research work -- no one else in her doctoral program was considered -- she knows this because her husband was in the program.
These kinds of differences make also make that some kids get into programs because they fit the mold, and some who are underestimated. It is so expensive to test to identify everyone and match needs.
Ren
