What you say makes sense, but I wonder if the amount of money they make re-selling our data would allow them to actually undercut the cost required to produce a "dumb" TV. So it's possible it would cost more for a dumb TV because it isn't subsidized by data reselling (I'm purely speculating here. I would guess dumb TVs would drive down the cost of smart TVs as they eat into their profit margins to maintain market share, which is important to the value of their data).

Nevertheless, a dumb TV marketing to me like that evokes an immediate "take my money!" response.