I think it's already happening. Back in the day, local and regional hip-hop sounded different from one another. Now you can pick up an album anywhere, and outside of vocal accents, it's gonna sound roughly the same as any album from another region. Pre-2005, not only did regions like East Coast, West Coast and South had different sounds, but different cities had a distinct style to them that was different from even different cities in the same region.
Localized slang is pretty much dead now too. Due to social media, everybody's slang is pretty much the same. There's still some regional stuff like Soda vs Pop, Y'all, and other stuff, but most ghetto slang is the same everywhere now.