It's like they handled mandantory driver signing on win64: One of the reasons 32bit wasn't affected is that this requirements breaks old drivers.
Similarily, on x86 you have two inhibiting factors: old systems without UEFI+secureboot that can run windows 8, and new systems that have to run older windows versions for some reasons (business requirements).
In a couple of years, there are only secureboot-capable Windows versions out there (and still relevant), and only secureboot-capable systems to run windows 10 on. That's a much more comfortable situation to pull the plug on non-secureboot boot.
Similarily, on x86 you have two inhibiting factors: old systems without UEFI+secureboot that can run windows 8, and new systems that have to run older windows versions for some reasons (business requirements).
In a couple of years, there are only secureboot-capable Windows versions out there (and still relevant), and only secureboot-capable systems to run windows 10 on. That's a much more comfortable situation to pull the plug on non-secureboot boot.