Don't buy such a TV, or mod it by removing the cellular modem. Same problem with cars, but generally quite easily solved.
For cars that's going to be illegal (or at least make it illegal to use the vehicle on public roads) at some point if it isn't already in your jurisdiction.
Yeah, in the future all TVs will be like high end cars today.
If enough people do this, new TVs will stop working without an internet connection.
If enough people do this, and refuse to buy TVs that do not work without an Internet connection, manufacturers will get the message and not make such TVs.