Just doing a bit of back-of-the-envelope math: 40 years of Spotify assuming 4% annual increases would end up being around $13,700. However, if prices increase a little faster, the price goes up fast. 6% annual increases makes it over $22,000 and 10% annual increases would make it nearly $64,000.

Individual tracks tend to cost me $1.29 or less so that's well over 10,000 songs even assuming only 4% annual increases.

Some people might listen to a huge variety, but others certainly use music streaming services to listen to a small set of songs.