It certainly does. An architecture isn't just about the ISA, but the culture around it too. The culture around ARM mobile phones and tablets heavily emphasized bootloader locking, which accelerated its spread to x86 too - which works contrary to the notion of openness.
> The culture around ARM mobile phones and tablets heavily emphasized bootloader locking
Virtually all of which are user-unlockable. But keep telling me how unopen they are?
(BTW, those of us who actually want secure systems very much appreciate the fact that malware can't overwrite my boot sector without a hardware-level vulnerability.)