I have to admit I don't like ARM. I remember seeing an interview with them after they introduced a new processor virtualization feature. The interviewer was excited because the technology would allow any operating system to be installed on an ARM processor. The spokesperson for ARM laughed and said of coursr but it would never be used that way. It was instead going to be used to allow licensees to lock away access to the physical processor ensuring all code could only be ran through the virtual processor giving vendors total control of anything ran on the processor. He then went on abou how ARM simply designs and licenses it's processors and it was up to the licensees if they wantes to sell a processor capable of running everything. He laughed again and said, but we all know that's never going to happen.
Those things are choices made by ARM device vendors. There are tons of open devices like the Raspberry Pi that use ARM processors, and x64 devices can be locked down just as effectively using TPM and system management controller features and secure boot.
Ya I know. Their licensing scheme gives them the ability to wave their hands and say not our fault, while specifically building the functionality in for vendors to lock awayand your right I'm not even going to get started on my feelings about secure boot. I've found I'm fairly diaagreed with on that so I'll just leave it.