We need to stop assuming that having no copyright means that the work cannot be monetized. It just can’t be monetized as if it was a physical object or service rendered. Vinyl records, tee shirts, patronage, book signings, lectures, anything that isn’t copyright dependent can be monetized easily.
The fans of art are aware that paying for it will help create more art they like. This is a personal connection that the fan has with the artist and keeps the art accessible for the casuals.