> Essentially, it's pretty clear that you can't make a successful company out of selling free software

If that is so the case, what about source available licenses similar to O'saasy.

Do they work?

Because personally, although I love foss, its a compromise and I am willing to make it for some of my projects if it means that I can get enough funding to work on it full time basically.

I don't think we know yet if these work, at least for more than 5-10 years. Mongo and Elastic are still kicking, so perhaps they do. But it's very unclear if they would have gotten where they are had they started with the current licenses.