Smart TVs are cheaper, not more expensive. You didn’t pay for those features—you saved money by having them foisted on you.
Even if true, maybe I liked those features (not advertising) and wanted to have them?
Then the advertising and the spying/telemetry are part of the bargain that you struck.
According to the GDPR, they cannot be.
But it's factored into the price. TV prices fell a lot during the last two years or so. They earn from the ads, they sell your usage stats. You get a subsidized TV. Don't connect it to the net.
Spit-balling; when will they put GSM chips in them? The cost of a data-plan could easily be reached with estimated figures for ads and selling usage data.
GSM is old-hat. The new cool is 5G chips embedded in TVs, and they are coming. And you won't be able to opt out unless you build a Faraday cage around the TV.