As a runner and as a coach (retired) I have taken a dim view of "potential." What we do is what we are "able." The yearning after one's own "potential" or the lusting after the "potential" of the kids you see goofing around and not "living up to their potential" is time wasted and only breeds disappointment for you and them.
That ranted, I think I might have had some better race results, if I'd taken more chances in pacing--gone oput harder and trusted that I could run with a faster group. I had the mileage and the conditioning and endurance, but I only rarely took the big risk of blasting off with the big boys and seeing how far I could hang. On a couple of occasions I did this, I was amazed how close to the front I finished, and way faster than before.
Maybe could have beaten my 2:47 mar. by 6 minutes or more.
Could have certainly gone under two hours in the 20 mi (best of 2:02)
and I certainly could have demolished my 10k best 0f 34:46 (all times above done after turning forty yrs.
jim