Basically, rapid communication gives people too much choice. They choose things comfortably similar to what they know. Isolation is needed to allow new things to gain an audience before they're stomped out by the dominant things.

There's a parralel view of innovation here that argues a positive linear relationship with speed of communication and innovation. I first saw it made by Simon Wardley , and I'll try to summarize below.

1. Innovation is a process.. first something (an idea, a particular sound, a physical product or software product) is new and chaotic, there's only one of it. Slowly, the idea becomes more refined and accepted, until it's essentially "commoditized" - everyone understands it in the same way, and understanding/using it is seen as a "cost of doing business" .

2. The speed at which something becomes commodotized is a function of the speed of communication (Wardley uses data from the agricultural/industrial/information revolutions to illustrate this).

3. New things happen because they're built on the backs of things which have previously been commoditized, this is what we're talking about when we say it's an idea/product/sound who's "time has come"

4. Therefore, the speed of new things increases with the speed of communication.

It's possible that both views are true, in that there will be less breadth of innovation, but that narrower band will happen faster with a faster speed of communication.