I disagree. There were plenty of people saying Vince should have stayed one more year. Yes, it could have hurt his draft status and money, but as you said in the long haul he would have been better off.
Andrew Luck risked his draft status. Leinart did hurt his draft status by staying in school. Draft status and money aren't the only factors that need to be looked at when making these decisions. In my opinion, Griffin's draft status or rookie contract is not likely to change much if at all if he stays one more year unless injured, which is the gamble.
I don't think all cases are the same or things can be overgeneralized to apply to every QB. Each circumstance is different. That is why I responded specifically to your comments about Aikman and Manning. Their situations were very different. They say they benefited by staying an extra year and I believe them. I also believe both needed to stay, especially Aikman, but since Griffin is in such a different situation he doesn't need to stay. Sure it can help, but isn't needed. That doesn't mean every QB who has been at school for 4 years with one redshirt year is ready. You would have to look at the whole picture to make those determinations. In Griffin's case, he is ready in my opinion.