Many of the most successful open source projects I can think of were funded by universities (Linux and Gnu) or natural monopolies (Unix). Their creators didn't become billionaires, but the sources of money were willing to pay them a comfortable living. Maybe it's the expectation that open source should be a massive fountain of wealth that is the real problem.

> Maybe it's the expectation that open source should be a massive fountain of wealth that is the real problem.

Maybe. But I also think that kind of funding for open source you talk about is not there for high-complexity projects in the present time.

It's not that I don't like that traditional model. I am legitimately worried it is no longer feasible.

Well, there is an option of selling services which is even worse, both for developers and the product itself.

Or, there are Fair Source License / Commons Clause / Business Source License /... that allow developers to capture some of the value they generate, but this of course means they are not open/free/libre because they limit some of the freedom to accomplish that.

Pick your poison. :)

Vue.js as an example

Do you know how the people who work on vue.js get paid? Do they have fulltime jobs as employees? Do they get paid to work on vue.js?

I find in general it's easier to get free labor on something the newer it is. Both because it's more exciting, and because the more 'mature' something gets the _more work it is_ for _less gain_, there's more time dealing with backwards compat and filing off rough edges and keeping the existing code just working, which is all less interesting to do for free. Plus, the more mature something is, the _more work_ it _takes_ to keep it going.