I don't know why you're downvoted, there's already screens currently in development that have precisely this. They should hit around late 2021 or early 22. There are SOHO routers in development that have this (Q1'21), and the 5G modem isn't even for your usage, its for the manufacturer to push/pull data. There's a side-by-side fridge/freezer that has this already on the market. There's a (commercial) coffee machine for installation in to offices that has this.

Only if there's enough users who refuse to give their TV wifi to justify such a crazy expense. Which seems highly unlikely.

There are IoT SIMs available on most major carriers, which are intended for economical occasional low-data usage on large numbers of devices. They're popular in GPSes among other things.

5G is looking to reduce the cost of them further as LPWA is a key part of the standard.

maybe one way to fight this is by finding a way to abuse these SIMs/connections to use a lot of data en masse until they get cut off or dropped altogether.

They can easily be remotely disabled if there's any suspicious activity, ie to any other server than the telemetry backend.

Exactly what I meant, and then you use their own SIM to DoS or DDoS them until they or their network provider disconnect the service.

This makes me remember the guy who was pulling SIM cards out of these IoT car boots and putting them in his phone for free 4G service.