Canon issues a "ballpark figure" for camera bodies in regards to an "estimated expected" shutter activation count. There is nothing guaranteed in this. It just is a round figure implying the engineering that has gone into the particular model.
Yes, shutters do fail. It may be at greater or fewer than the "spec". But it does happen. And Canon service does handle shutter failures, although if the camera is out of warranty it costs, I believe it can cost somewhere in the area of $300USD, but that's just an impression I've gotten from forum posts -- I've never had to have one done myself.