Ignore Scarf's success for a moment, and focus on it's goal. Do you think FOSS developers should be compensated for their work? If so, how do we make that happen?

I think Patreon-esque approaches + consulting is doing a decent job.

I actually disagree with this. Patreon doesn't target contributions from companies, only other indie developers for the most part. I've seen massive OSS projects that only get a very small amount of donations, so it's not a great solution for most developers.