I've seen so many random industrial devices and parts come into our plant that have their own cellular it's wild.
In a television it's an added cost and it's unclear if serving ads really can offset that extra $25-100 of hardware (and included data) you ship on a $200-1000 television.
It's also unclear to me if the low data packages they come with would be enough to serve meaningful ads to begin with. Those devices usually come with a fixed plan of 100MB/month for 5yrs (or along those lines). Modern smart tv ads are very often video or at least hi res images.
Amazon seems to have done the math and found that it makes sense to give a $20 discount on a $180 device if it lets them display very unobtrusive ads on the lockscreen. So I don't think you are correct.
> extra $25-100
Your estimated costs are off by at least one order of magnitude, probably two.
Of course none of this makes much sense in a world where smart TVs have ubiquitous wifi, most consumers have one, most consumers run the stock OS, and most consumers connect it to the public internet. It would be entirely viable if not for that status quo.
Not all mobile data APNs go to the Internet. You can't resell an IP service that lands on an RFC1918 network with exactly one IP:port available; the API endpoint.
Not saying I've seen this in devices, but I have built and run mobile data networks with private APNs.
Well... most TVs already have a WiFi/BT chipset for stuff like advertisements or, especially with Apple, high-bandwidth video streaming. There is already a radio module present, but (IIRC) you don't have to disclose what exactly that module is capable of.