Well, on one hand you had one line in a table in a formal web page.

On the other, you had that very awkward phrasing (if he merely meant ‘latest’):

because Windows 10 is the last version of Windows, we’re all still working on Windows 10,

But maybe that was a misunderstanding and he did mean ‘latest’, but in the flurry of internet coverage, Microsoft never issued a statement highlighting the misunderstanding. Instead they let that run rampant.

In fact, it was very consistent with a lot that happened with Windows 10:

• The mass “free to upgrade for everyone going back to 7” toward the goal of getting their userbase largely on a consistent vintage that is more supportable
• The twice a year major updates that were pitched as ‘new features and functions’, with a more ‘rolling release’ feel

So while certainly that one lifecycle page did have it stated, I have to wonder why Microsoft was mum on the subject even as their community was ‘getting it wrong’. I wouldn’t be surprised if the reality is that they were seriously considering it. That guy might have even meant ‘last’ because he thought the ‘eternal update’ camp were going to win out.