That's the speculated reason why Microsoft had to skip Windows 9: because in the late 90s, software were checking for «starts with "Windows 9"» to identify Wind

That's the speculated reason why Microsoft had to skip Windows 9: because in the late 90s, software were checking for «starts with "Windows 9"» to identify Windows 95 and 98... and some of those checks still exist and would had identified Windows 9 as Windows 95/98.