The nuances of the game aren't the same at D2 as at D3. I'm almost positive, despite having not played D1 in over 11 years, that D1 is different as well.
HD is not HBD with hundreds of roster decisions to make. You recruit your 12, maybe you redshirt one, maybe you cut 1-2, then you play your 12(or 11). The nuances of the O/D are learned at the level you play. The guy that works at D3 is a complete turd in D1. Recruiting is different at each level.
There just isn't much value in playing 5-6 seasons at D2/3 before going to D1. My guess is the better users are going to beat my *** at D1 while I learn the D1 game.