People noticed, there were videos about it at the time, we just stopped caring about a number. Apple did the same thing and skipped an iPhone number afaik.

because calling it Windows 9 would have messed up software that checked if it was running on Windows 95.

I always just assumed 7 ate 9… I’ll see myself out.

Skipping 9 was due to a combination of marketting ("It's nothing like 8 was, we swear! It's not even 9, it's 10!") and ye olde third party software developers making the poor decision to query the OS name instead of the OS version to set some compatibility stuff.

Oh yeah. The number 9 is superstitious in some East Asian cultures, like the Chinese. Its pronunciation is similar to "unlucky" or "suffering" so people try not to use it, like some buildings skip the 13th floor. But it's not unique. In Japan, the numbers 4 and 7 sound like death so they use alternative pronunciations. Another popular Asian belief similar to Astrology divinates personalities based on blood types.

Since Windows is a global product, MS execs decided to skip the number due to cultural sensitivity. They also wanted to close the gap with the Mac versioning and present it as a big improvement over Win 8, so it was probably a strategic decision for various reasons.

They skipped to 10 because it was going to be the last version of Windows and just be updated from there. Then they scrapped that and released 11.

I wonder if 8.1 was intended to be 9 and was never released as such