I ran this by the music historian Brad Kay, who confirmed that Jagger had his facts right. Thanks to Tyler for posting this and more thanks to Gut(?) who commented:Jagger, of course, studied economics at LSE and is known to be a fan of Hayek.
...people only made money out of records for a very, very small time. When The Rolling Stones started out, we didn’t make any money out of records because record companies wouldn’t pay you! They didn’t pay anyone!
Then, there was a small period from 1970 to 1997, where people did get paid, and they got paid very handsomely and everyone made money. But now that period has gone.
So if you look at the history of recorded music from 1900 to now, there was a 25 year period where artists did very well, but the rest of the time they didn’t.
He is also the primary datapoint for the observation that economists do it with models.