G'day Intellia!
I think you and David have a few big misconceptions about Itanium and Epic...
It would never work well for the desktop by it's very nature. The design theory behind Itanium is to strip away all of the handles that we use in x86, and just run very fast highly optimized code. This was fine for the server world because when Itanium was being developed, servers ran very few programs anyway, and speed was the most important thing.
Microsoft has had Windows XP-Itanium for years now, but the rest of the software developers have been reluctant to completely rewrite their applications in EPIC without a large enough base. At present, there are less than 2000 applications that are written for Itanium. You can't really blame them because as it turns out (and as Intel couldn't have foreseen), x86-64 runs the existing apps just about as fast and requires little to no changes be made.
Apple would NEVER write their OS in EPIC because none of the apps that run on the Mac would work on it...