Yes yes, I realise that this sounds like snobbery, but I have specific reasons for thinking that they (we) don’t.
When people sing (well) they sound like West Coast Americans. This is regardless of how heavy their accent is in speaking. For an example would be the songs in the movie The Commitments.
An Australian friend talking with my mom said that he was softening his accent while in the US so he could be more easily understood. Further, he said that it was actual easier talking that way.
As a West Coaster, I couldn’t “soften” or “lay on” the accent. I can’t even begin to think how I could try to do so. While as I can perfectly well think of how to do so with any other accent I can do myself.
There is no “regional accents.” I couldn’t tell you if a person came from LA or Oregon, let alone which area of town he was born and raised in. The closest I have ever experienced was when I called the big interstate freeway “The Five” rather than “The I Five”, which is a dialect issue rather than one of accent.
And of course that everyone else from the area seems to agree that we don’t have an accent.
I notice that even just watching movies from the fifties, like Casablanca that there is some sort of accent (which I assume to be the Californian accent of the time (?)), like “Frankly my dear, I just don’t give a damn.” Or comparing Steven Hill to Peter Graves in Mission: Impossible, where Hill had it, while as Graves did not. What happened?