The other big earner which wasn't mentioned here is publishing income. Now this only works if you're the songwriter but having an enduringly popular back catalo

The other big earner which wasn't mentioned here is publishing income. Now this only works if you're the songwriter but having an enduringly popular back catalogue can be worth a lot of money. David Bowie famously sold bonds on a ten year income that was worth $55 Million. On a smaller scale, I can't find a source right now, but I remember the NME carrying an article about Lee Mavers who wrote 'There She Goes' and that single song earned him yearly royalties of around $50,000. So you can imagine, all you need is a small back catalogue of well known and well played songs and the residual income can be pretty good.