lol not really music still is what brings them money with donors songs they sell to customers and all that,and the rest comes from their various type of investement,its the other way round for those who are not too active anymore in the big stage
for example a source of income many have is renting,some who bought a lot of houses rent some of them where they never lived and will never live and since its in lucrative areas they get good money or they have houses which they have transformed into appartments so they have multiple rent at the same time