I have 2 comments :
1/ this is probably the most accurate popularity barometer I’ve ever seen for U2, although it clearly pushes the latest releases, which has more to do with the way people consume music.
2/ Reminds me how much I love this band. Apart from 2-3 really off putting songs, I can appreciate their entire body of work.
The most accurate popularity barometer for U2 is their album sales and the ticket sales for the tours. Spotify, which is a slice of the streaming world and did not even exist before 2006, doesn't really scratch the surface when it comes to U2's entire career. The demographic is much younger than U2's fanbase, and has a high percentage of listeners that have never purchased a physical album before.
There was music that was extremely popular in the 50s, 60s, 70s, and 80s, but you wouldn't be able to tell that from spotify numbers. Again Spotify was created in April 2006, and wasn't widely used until 5 to 10 years later.
If you want to know what was really popular in 1982, you would need to use data that was collected in 1982 to accurately measure that, which is what Billboard Magazine and RIAA do have.