Great comment. Thanks!

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.

This is an interesting idea, reminiscent of, e.g. Lakatos's view of the philosophy of science. He argued that we shouldn't let new theories be discarded too quickly, just because they seem to have some things going against them. Only if their main tenets prove to be unfeasible should we discard them.

I think premature convergence does occur regarding the spread of ideas (memes), too (though it obviously varies). I do think, for instance, that what you describe in music has to a certain extent happened in analytic philosophy. In the early 20th century, several "scientific" approaches to philosophy developed, in, e.g. Cambridge, Vienna and Upsala. Today, the higher pace of communication leads to more convergence.