The premise didn't seem to be that Alabama players drafted in the first round are any worse than players from other teams - just that they are not any better than those from other teams. Many first rounders don't have spectacular NFL careers, and a few never see a second contract. Alabama players don't appear to be immune from that concern.
This article strikes me as a response to the general notion that Saban's players are better prepared for the NFL than players from other programs. So far, this has not proved to be consistently true. That doesn't make him any less spectacular as a college coach. In fact, it might demonstrate that he is an even better coach than some realize - that his players really aren't that much more gifted, but he gets more out of them.