or it's because : " ho shit Apple are already at os X (X for 10) so we will release windows 10 to catch them " ^^
Nope... heheh... it's pretty much just this: "code that looks for Win9*"
All of those apps that don't run if the platform is Win9* would fail to work on Windows 9.
Always though the years as versions thing was super dumb... funnier still when they barely released them in the year they were named for. I think Windows 95 came out early 96 and Windows 2000 was like December 2000 or something.