All of those genres can be linked to one another and you can continue on down to extreme levels. Rock, punk, metal, funk, country, soul, and reggae alone barely touches on the diversity of string instrument based music. Is this a naming problem for you?
Every noise at once attempts to show the extremes to which music can be classified if you haven't seen it.
I don't see any signs that this evolution has ever stopped or will stop. Artists are obviously limited by physics, what sounds pleasant to us, the instruments that are available, and what is currently in fashion. That we'd have more unique music in a more isolated world seems like a pretty crazy claim to me.