I remember about eight years ago, back in 2002, I had a Windows CE (PocketPC) device, and this is what I thought:
Windows98/ME was a piece of garbage. Windows 2000 was a good improvement, XP is already a step downhill. It's time for them to rewrite the Windows codebase and throw out all the legacy code -- no more emulation. Hey! Windows CE is a fresh tight OS, written from scratch. It would be really cool if Microsoft did an excellent job on Windows CE and groomed it as the eventual replacement for Windows XP. It would be a great way to leave all the legacy code behind and fund the development of a neat new clean implementation of Windows.
Fast-forward to now:
OSX is great, but it's big and accruing legacy code. iPhoneOS is focused, trim and almost entirely fresh. Apple shipped a new Tablet device, running iPhoneOS. Apple is on the crux of releasing a new set-top TV device, running iPhoneOS. Could Apple actually be in the middle of pulling off that super-slick move I hoped Microsoft would've done eight years ago? It's certainly starting to look like it.
Fast-forward another few years and OSX may be deprecated. Isn't that kind of what Apple is saying with WWDC by being entirely iPhoneOS focused? It wouldn't be so far fetched to see MacBooks shipping running a nicely tooled hybrid iPhoneOS. Then again, who's to really say we'll still need/want the laptop form factor?
If Apple does pull it off, that should make it into some kind of Hall of Fame.