Earlier quoted context omitted.
I have a "smart" tcl tv I bought during a sale. The only thing it costs me is that it takes somewhat longer to turn on than my "dumb" dell monitor. It's not connected to the internet, it doesn't show me any ads. When I (rarely) turn it on with its remote it boots to the last used input. If I turn it on through my set-top box, it boots to the box's input. The box can control the TV's sound volume with its own remote,…
I do something similar with an LG TV, but my point was you don't really have many good options if you want a TV that doesn't at least try to track you and the average consumer doesn't really know it's happening nor how to avoid it. Also, using a set top box on an external input is not free from tracking as most smart TVs use screengrabs and automatic content identification to figure out what you're watching even then…
But the prime experience was so horrendous, everything lagged like hell that I just couldn't keep using it. So I went ahead and did a full reset, which got rid of the ads, and I connected my ISP's provided box. I didn't try the broadcast tv performance, since I didn't have an antenna cable on hand.
Now, I don't know about other markets, but here in France basically everybody gets their provider's box, even if it's only for public TV. It gets you nice affordances such as a generally better picture and the ability to pause/get back in time. Those boxen usually come with the usual streaming clients, too.
So basically, there's no need to connect your TV directly, even if you're not paranoid.
Sure, the TV can do its screen grabbing, but since it isn't connected to anything, the only possible issue is for its buffer to fill up and somehow break. This hasn't happened yet on my specific TCL.
However, I do realize that my ISP can also know what I'm watching and sell this information to "partners". I've yet to see any ads on their box, but I wouldn't bet the house this will never change. So I agree with your last point, this will probably continue going downhill until we either see the public waking up (on which I don't count at all) or some regulatory action (which seems somewhat non-nil, especially here in the EU – but they seem to have bigger fish to fry, such as listening in on my chats themselves).