> Music is, in the last 15 years, demonstrably homogenising though

This is definitely a trend that isn't unprecedented: the popularity of grunge was in some ways a reaction to the homogeneity of music during the 80s. Rock was a rebellion against pretty much all mainstream music at the time it became popular. Our generation had indie rock. Music is definitely one arena where there are identifiable ebs and flows in terms of creative output and commercial dominance of a particular sound.

I suspect that a similar reaction to the ultra-commercialized nature of FB/instagram/reddit. There certainly seem to be enough dissatisfied people that we may see a 'kill your television' moment for social media in the next few years.

I agree that there is a bit of a cyclical nature to the homogeneity of music, but the homogenisation we've seen in the last 15 years has been unprecedented in modern times. It's not just the genres, it's also the people involved in the industry. The number of top flight producers is much smaller now than it was 20 years ago, and those producers are involved in almost all the mainstream chart music. The number of writers is smaller, and the music gets produced in a similar way, lessening the importance of musical ability by the artist.

My personal theory is that the movement away from 'record stores' has really killed discoverability of new music and genres, and most of the new platforms just feed you more of the same music you already listen to.

It will be interesting to see what happens in the next decade, you may be absolutely right about a backlash against the ultra-commercialised nature of some of our modern toys.