1. Direct voluntary payments by their audience (one-off/recurring).

2. Live shows.

3. Payment by various entities to sing something.

4. Organizations (the state, corporations, philanthropic bodies) which sponsor artists to work on their art without having to also do the work of financing themselves.

Still, it's quite possible that would fund less than are funded today. To that I would say:

1. It would still be a reasonable trade-off.

2. It would level the playing field somewhat between today's popular performers/artists and the vast majority of their peers whom, today, aren't funded.

3. Communities should motivate themselves, and organize themselves, to support local artists on the individual level, and to provide facilities such as music rooms, instruments, recording studios, professional training/lessons - for free or a symbolic fee, to local music artists (and ditto for other kinds of art) - so that at least people don't have to pay to engage in their art.