I think some of this comes down to the blame game.
I won't mention any names, but you know these guys... They come in here every year, focus on a drafted player that has outperformed their draft position, then pronounce that we should have KNOWN to take this player, and we didn't because our GM sucks, our coach sucks, our mascot sucks...
They'll say... we should have known to draft Brady, we passed on him because we were stupid. ...and when we respond, yeah, every other team passed on him repeatedly, as well. Then all we get in response are crickets as these guys slink back into their basements until next time.
They live on outrage... and anger... and envy, and fans like this are why many are so risk adverse. GMs start to fear making a mistake because of their unwashed fanbase.
EVERY PICK IS A RISK... EVERY DAMNED ONE OF THEM... but we took several shots on greatness last year. We took two very young players and a guy coming off a serious injury in the first last year, and we did this because we are shooting for the stars with our picks. I hope we keep doing that.
All of this said, to come back to one main point.
Taking a RB early is the safe move. Pay a lot more in money and draft capital, and get a higher percentage chance of getting what you want. Waiting til later and taking a guy that you think is perfect for a particular job on your team, or a guy with fewer carries in college, but great traits... THAT is taking a home run swing, and I sure hope we pass on the 'big three'.