I imagine it won't be long before the TVs come with eSIMs to connect directly to Tmobile/Verizon/ATT, and maybe add some cameras in the borders to track eye movement.
Then the advertisers could buy more accurate information to improve product placement in movies/tv shows.
The sci-fi version could be a TV that can recognize what kind of things are in the room or clues for the viewer's socioeconomic status and emotional state to bring up content (or even change it in real time) to maximize resonance with the viewer.
The cost is probably still too do prohibitive to do so.
I worked with IoT devices, generally the cost per GB of data is around dollar per GB. I doubt you would make that back in advertisements.
Also, there is cost per SIM so you wouldn't want situation where SIM is active if you don't need it which is why alot of IoT devices have you setup with a phone because they turn SIM on when you sign up for their plan. If consumer never puts TV on Wi-Fi network or cooperates with the phone, then you would have keep each SIM active and turn it off when it checks in via Wi-Fi. My guess is cost is not worth it if you get 98% cooperation. Write off 2% and call it a day.
The cheaper play (which could be implemented today, likely with few HW changes) would be to just use BLE or another 2.4GHz proprietary protocol to broadcast your usage data (maybe encrypted with a vendor key - let's be generous) to another TV or refrigerator in your area that is already internet-connected.
Then the advertisers could buy more accurate information to improve product placement in movies/tv shows.
The sci-fi version could be a TV that can recognize what kind of things are in the room or clues for the viewer's socioeconomic status and emotional state to bring up content (or even change it in real time) to maximize resonance with the viewer.