TMC, the problem of "plethora of technically obsolete hardware" should be similar at every WinOS switch-over, but I simply don't recall seeing "Win7 downgrade rights to Vista/XP" ever.
Do you remember seeing such a statement?
I do remember there was a wariness about moving to Win7 simply because of the very bad experiences that Vista's first waves suffered. I remember there were a lot of articles full of Win users saying, "I'll wait for Win7 SP1" but, after a few months, I saw more and more articles with quotes like, "I'm not waiting - Win7 is good enough to switch without SP1..."
In all of that, I don't recall a single ad that stated "Downgrade Rights From Win7 To ___".
And in those days, PCs were still moving quite rapidly, so inventories were higher then than in the last year.