He's got a good point, but at positions that are filled by committee like RB, I'm not sure it's entirely accurate.
If we draft a WR in round two, I don't for a second think that spells the end for Nicks and Cruz. However, it may be the end for Hixon (it could never be the end for Barden, because as Treehugger will attest to, Barden is going to have a monster year with 3,000 yards and 35 TDs).
Same with backs. It's a committee position these days.