Throwing Jerry Nixon under the bus...
"given they clearly said Windows 10 was the final release"
They kind of never did. Jerry Nixon (a developer evangelist at MS) said "Windows 10 is the last version of Windows." So it's true that he said this. Once. It's also true that when asked about it, MS has never confirmed this to be true. Sure, they didn't deny it either.
This quote is very much over-reported.