That was my first thought as well. It's clearly not reasonable to assume a customer bought a product without any knowledge of arbitrary future changes in the legal terms but understood that the product could cease to provide the same functionality they bought it for later if they didn't accept those unrelated changes. This ought to be grounds for returning these devices to vendors as unfit for purpose and demanding that either they are fixed to continue working properly or some fair level of compensation is paid.
Also, since we're getting some new data protection laws across the EU next year that are heavily weighted against organisations that process data, someone who is upset by this could probably annoy Sonos by doing things like accepting the policy, getting whatever updates they need to keep their device running, and then immediately giving notice that they withdraw their consent for processing any personal data.
In the long term, I think consumer education may be the best solution to the problem of normal devices depending on fragile remote facilities. It is illegal to sell cigarettes in my country without showing very obvious warnings about how smoking is harmful to your health. Perhaps it's time that any software or electronic devices that rely on someone else's servers or remote hardware to function have to have 1/3 of their packaging (including 1/3 of the total screen area for any web pages or app purchase screens) used for a big statement that this may cause the software or device to stop functioning at any time, or to give an actionable guarantee about how long such support will be provided for as a minimum, and that any advertising for such things has to describe the "purchase" in terms of being a rental rather than buying something.