Tom Yager has an interesting article about Apple closing their OS X x86 source code and making it impossible to re-compile the kernel. Apple's argument (according to Yager) is that only a fraction of a fraction of people ever re-compile an operating system kernel. The "but it is only a few people" argument is really easy trap for an organization to fall into; however, there are a number of issues with the argument.
First, I have spent many years working in open source and have learned that having the freedom to look at the source code and recompile it or otherwise manipulate it is something that many people want. The reality is that only a fraction of a fraction of people every actually look at the source code and even fewer modify it, but knowing that they could access the source if they ever needed to is a powerful and important feature for quite a few people.
Second, this fraction of a fraction of people who do recompile the source code tend to be a very vocal minority, and this minority usually includes the geeky types who have quite a bit of influence over others. These are the influencers, the bloggers, the ones who recommend computer gadgets to their friends and families because people trust their technical expertise.
According to Angela Gunn the Apple source code fiasco along with the iPod sweatshop controversy is creating a persecution complex for Apple. I do not have any experience with Macs; however, I do have geeky tendencies dating back to my time as a Unix sys admin, and I have experience with Linux. I am one of those people who has recompiled my Linux kernel just for fun.