Steve Carell To Leave The Office?

How much of The Office and its success can you attribute to Steve Carell, who plays regional manager Michael Scott?  A lot, I'd say, since he isn't just brilliant in front of the cameras but behind them as well, having written and directed two episodes and served as a producer for most of the show's run thus far.  But that all could be coming to an end after next season (the show's seventh), as he recently said in an interview that he'll "probably" leave once his contract is up.  If Carell does leave, would The Office continue?  Should it?  I think NBC would run the show into the ground and be willing to replace every single member of the cast as long as the ratings held up (see: ER) no matter how bad the show actually became, but as a big fan of The Office, I'd hate to see this happen.  More than anyone else on the show, Steve Carell is irreplaceable.  I hope he's just saying he's thinking of leaving so NBC will offer him more money in his next contract, which will be for the next billion years.  But even if that does happen, there's still cast members John Krasinski (Jim) and Jenna Fischer (Pam) or even Rainn Wilson (Dwight) and Ed Helms (Andy) to worry about.  Krasinski and Helms especially have movie careers they can focus on, much like Carell, as do Wilson and Fischer, albeit to a lesser extent.  When their contracts are up, what are the chances that they'll all stay?  Probably pretty slim.  Perhaps it's a good time to start preparing yourself for The Office's inevitable end, and hope that when it does happen, the awesome cast is still intact.