When we consider what caused Apple to make the Mac successful again, there are a couple of theories. For John Gruber, it is the superior quality, Mike Arrington points to the Internet as the great leveler, and Dave Winer chimes in with lack of malware. All of these are important factors, and they allowed for a lot of consumers to switch to the Mac.
But I believe that we underestimate the importance of the Intel switch with the corresponding Windows compatibility. It is what has allowed many people to opt for a Mac without giving up on their legacy software, especially for programmers wanting to try out iOS. There is a huge saving in complexity if you need only one computer, and so the ability to run all but the most graphical demanding Windows applications in a virtual machine in parallel to Mac programs is a huge bonus.
I believe this has greatly accelerated the supply of iOS programmers, and this halo effect together with the Mac App Store had quite a positive impact on the supply of native Mac apps.