So I agree with the premise of this article, but the glottal stop is found in many regional American accents.
The internet removes language barriers from lines drawn on the ground, and this small difference has sped up a still very, very slow process started by television. Language is evolving towards a single shared language, right now we can see the regional differences falling away between nations. TV has dissolved much of the regional differences within the US. The difference is still there, and probably always will be, but its a lot weaker than it was a few decades ago.