I miss the days of "standard British" pronunciation, in which actors were taught to speak a clear and concise "Queen's English"if they were going to be actors or news readers. Some of the British dialects one hears on their TV shows are too unintelligible. On most American shows, people don't use such extreme dialects.
The use of regional accents is a reaction against this. It was seen as snobby and elitist to exclude people who couldn’t speak in received pronouniciation English, so they did a quota of regional accents just like they do with women and minorities.