I haven't bought a consumer TV since... well, actually, I just haven't ever actually bought one except second-hand non-smart TVs a decade ago. Is it literally that bad? i.e. does everything show ads? Can you root these machines and/or install non-ad-based apps instead?
The primary objective is "growth and engagement" aka an ad delivery mechanism (or data collection mechanism for more ads down the line). The functionality of the product (if any) is merely a necessary evil (from the manufacturer's point of view) to convince the mark to buy & "engage" with the device. If they could get people to "engage" with it without any functionality they'd definitely do that instead.
Buddy of mine used to work in a kabab shop before finishing his IT degree and helped out there off and on. He ordered an installed some 48" monitors (simple HD TVs) and then ordered a few for himself. I think they could 2 inputs max, but that's fine for most purposes.