More importantly, I don't think consent is sufficient in this sort of situation. It has to be a real choice, so even if you choose not to consent to the change, you're not then losing out on something you already paid for or otherwise giving up your normal legal consumer rights as a consequence.
In a situation where the continued effective functioning of a purchased item is dependent on some other facility, and that facility and the related functionality can be turned off if you don't accept the manufacturer/vendor moving the goalposts retrospectively, I don't see much ethical or practical difference between using this dependency as a lever to force a customer to accept revisions in some other aspect of the deal and just doing the other thing without their consent anyway.