My dream for how to make money with open source is to create some software that is useful to people and then have a subset of my users pay me to implement, modify or maintain it for their specific purposes (example: "My accounting department would like quick books integration I'll pay you to add it in"). Given that i'd be the creator I should be the worlds foremost expert on it by default. Maybe that's naive?
I did this for 10 years, 2 years as a freelancer (barely getting by) and 8 years as an employee. The project has now completed its lifecycle.
You don't have to be a founder, you just need to be an expert. In terms of career development, I think the ROI is better on joining an existing project. But "progress depends on the unreasonable" and some people become founders nevertheless.
I did this -- working on open source founded by other people, from Bugilla to GNOME -- for two decades, and my experience is similar. Contract work is available for customizing open source broadly, and pays well, but it has all the common downsides of contract work. Notably, it conflicts with the growth-driven VC model which is where open source has ironically become a cornerstone.
This is possible. Folks have done it. But consider that by releasing the open source under permissive terms, like MIT, anyone else can come by and do integration/adaptation work, too.
That leads to a kind of cross-purpose incentives. It won't be in your interest to make the code easy to understand or adapt. It won't be in your interest to document how you go about fulfilling those needs. You may face conflict in promoting the availability of your own services through documentation or other materials about the open source project.
