Some linguists claim that television has little influence on the way we speak. We learn our accent from the people around us, not from what we hear on television.
My five-year-old grandson Oliver has been staying with me this past week. He uses the American pronunciation for tomato: [təmeɪtoʊ]. He lives in England and he does not know any Americans, so it seems unlikely that he has heard that pronunciation from people around him. I asked him where he learned it from, and he said it was from a programme called Pepper Pig.
This seems quite convincing evidence that he has learned it from the television, not from people around him.