Part of it is the nature of expanded passing systems that, since the 80s, have added more and more complexities and capabilities to passing offenses. Part of it is the rule changes that in the last decade have given quarterbacks more and more protection and denied the ability of passing defenses to negate and/or punish wide receivers in different facets of the game.
As a whole, the running back position just isn't a top tier value position any more, compared to offensive and defensive line positions, wide receiver, cornerback, and, of course, quarterback.
That being said, where does Trent Richardson's fate reside? He is, IMO, the best running back prospect since Adrian Peterson (AP is a solid piece of evidence of the lack of value at the RB position; despite being pretty much inarguably the best back in the league and racking up over 2,250 yards in the last two seasons in just 27 games, his team has only won 9 games out of 32...).
AP went seventh overall. Mike Mayock remains unconvinced that T-RIch is going to be picked in the top 10. Is it possible that Trent Richardson could fall into the teens? Or further?
There isn't a solid set of historical data to apply here, since this is the first era of football in which the running back has been relegated to second tier status. The trendlines will be set in the next few years, so we'll have to see how top prospects are treated.
But a back like T-Rich is relatively unique. His blend of power, balance and speed is very, very rare. He's got experience playing some of the best defenses at the college level as well as playing in two national championships.
His former teammate Mark Ingram was the first running back taken in the 2011 NFL Draft at #28 overall. The year prior, CJ Spiller led off the running back class at #9 overall. I don't see any RB being taken before Richardson, but it's useful to compare him not just to this class but prior top prospects at the position.
So what do you think? Is a three-down starting back with his resume worth a top ten pick? Does team need matter (and you could approach this hypothetically since pretty much all of the first 10 picks are relatively set at RB...more evidence that the position doesn't have a strong effect on the W-L record)?