Yeah, there is also a bit of this at play when Spotify talks about what they pay artists. They say they pay an average of 70% of revenues, but they don't explain that major labels get way better rates per stream, not just because of the volume of streams. It would be akin to Wal Mart boasting an average $22 per hour salary for all workers because their CEO makes $100M a year while all others make minimum wage.
In that first graph is says X 4 (Artist's Royalty Rate). So it is based on market share, and some rate, which they would have simply said is Y had it been the same for everyone.
