I worry about the new cellular standards that support large scale iot.

Search for 5g miot or 5g massive iot or maybe even 5g redcap

Existing LTE is fine. If they wanted to embed modems in the TVs they could do it now. I'm guessing they simply don't have to, simply because a huge number of consumers will dutifully hand over their Wi-Fi passwords.

This is exactly the situation we're in with new automobiles...

While this is certainly possible, I’d imagine this sort of thing would be found quite quickly and would result in a massive lawsuit if not disclosed on the package.