It’s funny how media widely misreported this, but what’s not funny is that people believe that to this day. Even in this thread people think Microsoft said that.
The quote is in the article:
Right now we’re releasing Windows 10, and because Windows 10 is the last version of Windows, we’re all still working on Windows 10,
They obviously meant Windows 10 is the latest version of Windows, but I guess misconstruing the quote got the clicks and then everyone went along. There was never any announcement from Microsoft, all of the “Windows 10 is the final version of Windows” thing is based on misconstruing the quote. If a reporter really believed this interpretation to be the case, it would be easy to just ask Microsoft, but they didn’t. Or did, got the “lol no of course it’s not last” answer and ignored it because that would make their clickbait article go away.