Anecdotes are useless in this conversation and you should know it. Nobody in our leagues would have drafted an 18th rounder in 2010, just like nobody in the DDL drafted Tanner Houck in 2014.
Being said, I find it easy to believe that Bryant, if he signed out of HS, would/could have debuted at 20 or 21, a la Correa, Fernandez, Lindor, etc etc etc.