@whitequark @foone This is a great point
I think the requirement could more simply be that all cables should abide by open standards only (with some exceptions given to grandfathered but well known standards like HDMI)
Then furthermore, manufacturers should be disallowed from inventing new standards if their use-case is already well supported (no inventing an "open-source magsafe" just to sell more magsafe)
Tightening the process for what gets accepted as an open standard would then eliminate competitors designing differing "open" standard implementations that do the same thing but are incompatible with competitor products. Some centralised group would be needed. If a standard already exists for something, it should be modified to accommodate new use-cases, not remade separately