Ricky Gervais writes that Steve Carrell is doing the right thing by quitting "The Office".

If his heart isn't in it, it's time. I will miss Michael Scott however......

CNN:
Ricky Gervais says, despite not wanting to say goodbye to Michael Scott just yet, Steve Carell is making the right decision by leaving “The Office.”
“It was expected of me, as executive producer, to persuade him to stay on,” Gervais wrote on his blog. “With syndication in full swing the more successful the show remains, the more billions we all make. It was tempting, but the truth is, I believe he is doing the right thing. He's fulfilled his contract and more, and is a huge film star now."
Gervais added, "I'd be lying if I said he should do more. He shouldn't. He should move on, continue to do great work, and buy a new house every time The Office is repeated somewhere.”