the end of L Carr?...he retired in 2007. what are you saying....if Paterno retired after the 05 season (which was supposed to be his last), and let's assume Tom Bradley took over, would we have won more than 1 Big Ten championship (05 was Paterno's)?......I don't know....maybe.
I guess Bradley would've benched Morelli for Clark in 07 (probably lose 1-2 games that year max), and recruiting would've been better to help us in the consequential years. but obviously, we won 08....so to predict much more after that is tough.....2011, D-Day happened....so we're talking about 06, 07, 09, '10. 2007 & 2009....you might have something there.....but obviously, no guarantees.
to go back to your main point....I agree, Joe stayed way too long. not sure when the right time was....probably after the 1999 season, he should've bowed out.....though, he knew that season ended in a whimper.
after what happened in 05....gosh, who wouldn't have been re-energized after that (though, what a way to go out...if he chose to do so.....talk about going out on top).....had a great run from 05-09.....but the bad recruiting led to the on-field downfall in 2010.....kinda got lucky in 2011...def overachieved.