Srini said:
After Wimbledon last year, he lost some drive definitely.
I don't think it was after Wimbledon that he lost some drive. He played very well at the Olympics, then won Cincinnati, and was doing well at the US Open until he ran into Berdych in the quarterfinals. He was the man in tennis last summer after winning Wimbledon (even despite losing to Murray at the Olympics), and I think he liked being the man again. He seemed to thrive being No. 1.
A couple things about the US Open:
1. He had a bye in the fourth round because Fish pulled out (maybe not playing that match hurt him a little against Berdych due to rust)
2. Andy Roddick's retirement. I think this shook Roger a bit and got him thinking "Oh wow, I'm one of the last guys left now." Roger lost the day after Roddick lost to Del Potro.
After the US Open he said he was "wounded." But he still finished the year strong and played extremely well in London, losing a close match to Djokovic at the WTFs. In Australia, he went to the semis and fell to Murray in 5 sets in four hours.
So, overall I don't think it was really reclaiming No. 1 at Wimbledon that cost him motivation, though I do think that his drive to do it all again now is probably not there because it was likely very exhausting for him to do it a year ago and now to do it all AGAIN would just take too much.
It's funny how NOW we all want him to have one last run when he already had his last run last year! Imagine in 2011 saying, "Roger needs to have TWO more runs. Not just one, but TWO more big pushes toward the top of the game!"
The insatiable nature of the human ego...