It's ridiculous that going to a Target/Bestbuy/etc you cannot find any non-smart TVs generally. I have had several older models of non-smart tvs that suddenly stop working after a few years. It's disgusting
A smart TV just means one that can show you advertising and hoover up personal data. This is additional revenue. What company would sell you anything else?
It's either because the non-ad-driven tvs cost more, resulting in too few sales to sustain (because no lifetime revenue from data sales) or the lifetime revenue from data sales is so profitable that companies take the risk on being undercut by a market entrant that will sell dumb tvs.
My guess is that the vast majority of people will trade data for a cheaper price point every time (my wife is certainly one of these people), so the market just can't support the volume of sales necessary to make the price point of dumb tvs competitive.