Actually, Bruce Springsteen and many others just sound like they've been living under a bridge. Any local accent is lost in the phlegm, raspiness and mumbling caused by years of poor health and substance abuse.

I bet sound engineers have a button that they push to make a guy sound like 'long-term homeless."

They think it sounds tough, I guess. Or like they've suffered and they really know what life is all about - it's dismal.
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Joe, I spend a week in Texas most years, and I have heard no special Texas accent. There can be a Western drawl, especially among whites who were born there, but the speaker could be from Texas, New Mexico, Arizona....

There's a saying on the east coast, "As soon as he opens his mouth, you know he comes from a square state.'" If you don't understand that, study a map of the lower 48 states.

Hispanics can sound different from Anglos. And it matters what the person's natural voice is like. An adenoidal, husky or nasal quality might be taken as part of the accent, when actually it's not.