Whatever Microsoft's motivations are, this new policy should have a deleterious effect on retail OS sales.
The advantage of buying a retail boxed Windows OS over the OEM Windows version that ships with a retail PC has been that you could move it to your next build (as long as you de-activate it from your current build).
That advantage seems to be lost now (assuming you move forward with newer processors).
Processor generations change every 2-3 years, while
the Windows OS lifecycle is 10 years, a gross mismatch.
It's especially bad for Windows 8/8.1 retail copies. Say you build a Skylake desktop and upgrade Windows to Windows 10 before July 29th. Anytime after July 29th, when you want to move that retail OS license to the next PC, you have to downgrade both the hardware
and the OS (
to 8.1 per Microsoft rules on the Win 10 free upgrade).
Sorta pushes some desktop builders to Linux, unless Microsoft lowers the price of retail Windows, proportional to the loss of migration capability.