Microsoft has improved with activation on a technical level, but I wonder how it all works.
It’s great to be able to get licensed Window 7 OEM CoAs activated on Windows 10 simply by booting with UEFI configuration, installing, entering the key on the sticker or running the Windows 10 upgrade from Windows 7. I’m not even sure whether one needs UEFI or not.
I’ve upgraded older ASUS, Lenovo, and Dell hardware using the 25-character license key (CoA) attached to its exterior, as long as I was using the corresponding edition of Windows matching that of the sticker’s. If you have a Windows 7 Home CoA, install Windows 10 Home; If you have a Windows 7 Pro CoA, install Windows 10 Pro.
The only hardware I have not been able to activate, at all, were custom built PCs without any original OEM-supplied license key.
Overall, I like how simplified the activation process has become, but I also like not having to buy new hardware.