It’s true that regional accents have diminished somewhat, or have at least reduced themselves to the point where they are pretty much comprehensible by all speakers of that language in that country. I remember when the Brits had to subtitle programs from Yorkshire because nobody outside of that region could understand them!
I’m from the north but I live in the South now and I don’t have any trouble understanding anybody except the occasional elderly rural white speaker or some of the rural black dialect speakers (who are completely unintelligible to anybody outside of their group).
While the effect of TV has been not exactly standardization, at least it has meant the halting of the “drifting away” of a regional speech to a dialect and then to a whole new language.
There’s an intelligibility standard for the major languages and that’s actually a good thing. Languages, real or imagined or invented, become part of nationalist fantasies and they never have a positive effect on human life.
For instance, what did Ben Franklin sound like?
I can't recall what the final analysis was.
I wager that Ben had a "funny" accent to our ears, though.
And off topic, but I lived in Baltimore for years, and I still can't imitate that accent.
New Yawk, Boston, Dallas, Minnesota, easy to emulate.
Bal'mer?
Can't imitate, but I know it when I hear it.