What 10+ year old existing commerical OS should Microsoft move their users to? You aren't really addressing the point. To users, OS X was the next version of

What 10+ year old existing commerical OS should Microsoft move their users to? You aren't really addressing the point. To users, OS X was the next version of Mac OS. Apple took NeXTStep and added a pile of classic MacOS UI and added APIs so developers could easily port their classic applications. It wasn't 100% new even to the users. Familiar UI. Same apps. If Apple has just thrown BeOS on their machines and it turned out be a success then there might be some argument for users and developers loving a 100% new OS. But, as it turns out, even an OS as advanced as BeOS is not what users and developers really want. Users want to be able to run their same applications in familiar environment and developers want to make use of their existing code and existing skills. Another way to look at it is Apple moved their users to their own "Windows NT" -- something that Microsoft also did around the same time frame with Windows XP.