Now you've mentioned Spotify, according to the Every Noise at Once website (which is an algorithmically-generated, readability-adjusted scatter-plot of the musical genre-space, based on data tracked and analyzed for 3,068 ((!!!)) genres by Spotify), "Rock" is the 5th most popular, with various subtypes appearing further on down in the list.
Given this list is generated by data from 100 Million Spotify users (so a pretty large sample size of music listeners), I reckon it gives a more accurate representation of Rocks popularity.
As an aside, Grime comes in 203rd place with Drill in a 412th.
Stick that in your pipe Bobby π
http://everynoise.com/everynoise1d.cgi?scope=all