I think Microsoft and Apple are on a good path: keeping the same major version number for their OS, and just continually bring out little changes.
[1] https://www.reddit.com/r/technology/comments/2hwlrk/new_wind...
For the five people on Earth actually affected by this, there's always compatibility mode.
I imagine it did play some role but as a child comment notes, the regex checks for Windows 9\d* in order to capture both 95 and 98 in a few languages that exposed versions like that probably played a much larger role. Accommodations that were made for those incredibly old systems could very easily have caused some big problems if they matched on Windows 9.
If there's a Windows 9 it might eventually turn into Roman numerals, so then you've got Windows IX, which could turn into Winix or Wix, or in a particularly bad case "Windows Icks".