Strong is relative. The regional differences in my generation (40) and younger mostly come from accent and not from the vocabulary, whereas for my parents and grandparents it would be both.

There is still local vocabulary: nesh, mardy, cob, duck being obvious answers, but more of it is dying out: tuffee, sile, causie.

In my experience, there's only a small subset of people who will get their accent from the mass media rather than their parents and the people around them. That accent will also almost always be an vapid pseudo-American one, mysteriously bicoastal, combining LA valley girl, 90s NY highly-commercialized hip-hop regionalisms, and barely enough of their local accent to keep from getting punched. Also, since 2008, the word "folks."

This is mostly I think wealthy and upper-middle class people, but there are also definitely a lot of strivers who just think they're better than everyone local, and don't want to sound like they come from where they come from, but like American surfer-artist-activists.

Same thing happens in the US, through. A lot of Americans relating to the television more than their neighbors. Even worse, since the accents in US media have become terrible and authentic local accents rarely heard, young US media addicts are often imitating British and Australian people who are imitating US accents.

I honestly rarely hear any authentic southern US accents in TV and movies, only imitation ones. Imitation of the representations created by a highly centralized media might ultimately and gradually turn all of us into caricatures, even of ourselves.