TV makes people sound the same
It is impossible for media to make people sound the same. Dialects keep changing and continue to diverge from standard dialect even though their dialect is not on TV and radio. Television is blamed for changes they have no or hardly any contribution to. People should realise that media does not cause changes; media just catches up with the changes.
Baur, L., & Trudgill, P. (1998). Language myth. In Baur, & Trudgill, Language myths. London: Penguin Books.