...Does any other popular consumer OS get that level of support?...
The real question is: does any other popular consumer OS need that level of support?
If Microsoft did not mess up the "next version" as much as they have done, there wouldn't be the need to stick with a particular version for so long.
As an alternative case in point, my three Windows PCs tend to stay with a version until that version is no longer supported. While my single Macmini has had the OS upgraded to the newer version a few times, and all at no cost or bad experiences to me.
With the Macmini, the OS upgrade to the next version has been a fairly smooth experience, as opposed to a Windows OS upgrade to the next version which is more of a traumatic experience.
Maybe that is the cause to the need to have long support cycles for Windows OS versions?