Two points here:
1. Williams's off-the-wall brand of humor is far more of a fit for a pure sitcom than Fox's, especially now that Fox has pretty much been reduced to a sympathetic figure.
2. The article makes a key point here, and that is that the lead-in is the key factor. The Big Bang Theory is the hottest sitcom on television today, so of course The Crazy Ones is going to have more people watching at the start, and thus staying on the channel even if they don't watch it. The Michael J. Fox Show, on the other hand, has nothing. It's on NBC, a network that has been struggling for years.