Apple to slow down the pace of major OS X releases

As you can read on News.com, Apple plans to slow down the release pace of major OS X versions. Starting from Mac OS X 10.1 (which was the first really usable version of OS X), Apple has released a major update once a year. I am wondering how much they will slow down.
Microsoft has always been very “slow” in releasing minor and major versions of its operating system. In various books about software engineering and programming techniques, you can read that one should never change too much at one time, because the risk of loosing control over the changes and “getting lost” grows with the number of major modification made on a piece of software. I am asking myself if that rule is also applicable to operating systems. One indication to prove that theory is that Microsoft has been forced to push back release dates of Windows many times. I guess it’s very hard to get the right amount of items on a feature list for a major OS release, since you want to add value for the majority of all your customers and on the other hand, it would be more reasonable to keep the number of new features concise.