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.
Perhaps, as with various other unreasonable or one-sided provisions, there should be a presumption under consumer protection laws that any such terms are invalid, that any substantial change in an agreement must have the customer's explicit, active consent, and that if the customer does not consent and this results in something they purchased no longer providing the expected benefit then the usual protections about broken purchases should apply. You'd have to be a bit careful, because sometimes these self-updating terms are used to deal with minor changes in the legal landscape that are formalities with no real impact on anyone, but that seems like the sort of thing a court could sensibly decide in the event of a dispute.