65,000 listeners a month – $800 in revenue. 1.23 cents per listener per month. That works out to 14.7 cents per year. To earn a modest $50,000, you would need ~360,000 monthly listeners. This doesn't seem sustainable without outside sources of revenue.
Correct, this is why bands tour and sell shirts and other merch, and for most, work second jobs. As an anecdote, friend of mine is in two or three bands at any given time and bartends most nights he’s not playing shows. Spotify makes it easier than ever for an artist to get their work out there, which is great, but it’s similar to the publishing world, where most authors who self publish do so into the void.
Besides, who doesn't love a good tee with your favorite band's lyrics on it?