Neither is Metallica. That's not how this works, isn't it? People come because they know the band name, remember good old songs, and so on.

GNR doesn't have any concerts right now, so I can only use this data: https://www.rateyourseats.com/tickets/guns-n-roses

The average ticket price for all shows was $365

That's still much more expensive than 80 EUR (which includes taxes).