Bingo.
In specifics, many extremely talented football players fail in the NFL not because of a lack of talent but because they just don't figure it out. Every player drafted in the last 3 days has talent, but most will not make it. The window is small and they have to seize the opportunity. It's not enough to be the best athlete on the field, for one thing it is probably no longer true. And too often these kids think they've "done it, mission accomplished" when they get drafted, not realizing that it has only really just begun and they haven't seen anything yet.