This is starting to seem trollish. If you are incapable of addressing the original comment I wrote about x86's proprietary nature then these rhetorical questions don't add anything. If you are, then please let's hear it (not in the form of a vague rhetorical question but a coherent argument). That said I'll humor you once more.

> Do they sell ARM processors and motherboards?

Yes some of those boards are essentially motherboards with ARM processors on them.

> Are there even standard sockets for them?

Not that I know of for ARM chips. If by "standard" you mean Intel-proprietary or AMD-proprietary, then there is be no reason that an ARM vendor or ARM Ltd. itself could not define a socket specification. That's not a matter of openness or proprietariness of the platform.