You could do a random sample of non-prisoners and you'd get as many potential Georgetown law professors as in prison.
I don't doubt that there are a lot of prisoners that would thrive with encouragement, but you also aren't being realistic: the people who end up prison often end up there because they made a series of very bad choices which were the result of being raised in an unfavorable environment. Some people in prison will never be rehabilitated and they certainly aren't going to became Georgetown law professors. Prison tends to select for people who aren't law school material, so the likelihood is not surprisingly very low. It's not something that can be fixed by pleading to the better angels of our nature.