Windows 10 is no Vista.
(Borrowed the title from another author).
Times have changed since Vista.
In the Vista era it was almost plausible to argue that Windows was still the only answer, and so it was relatively easy for Win7 to recover from the Vista debacle.
Courtesy of Vista, Windows 8, and other developments (particularly tablets and Android), it has become clear to lots of people (outside the world of the Certified Microsoft Dependent IT department) that for routine stuff, there are multiple alternatives to a Windows desktop/laptop.
That's the big difference between now and then, and that on its own would have made life difficult for the successor(s) to Windows 7.
Win8 was an irrelevant mistake, that seems to be admitted now, and the various self inflicted design and implementation faux pas in Win10 make it even harder for Win10 to appeal to people who don't care about MS but just care about browsing, email, music, pictures, etc.
It may not definitively be the beginning of the end, but it's starting to look like it could well be, especially where Joe Public is concerned. [EDIT: And it's probably too late to recover, given that the alternatives are out there and demonstrably workable, and some of them are even fashionable, unlike Win10]