I don't necessarily buy the idea that iOS's lack of complexity and compatibility is the reason for its success. You can already see complexity and compatibility problems 4 years in with iOS. Things like the undiscoverable double click method to call up the app drawer and the weird double pixel support for iPhone apps on the iPad are already here. iCloud seems to be poised to basically become the filesystem for iOS devices (if my prediction is right). Even Gruber says that iOS will eventually consume Mac OS X in this article. So if iOS is going to continue growing in complexity and trying to maintain compatibility over the years while also trying to remain user friendly, why is attacking the same goal with Windows from the opposite direction any worse?