I've been working on Open Source software for 30+ years. There's no money in it, if your idea for making money is "accept donations". I don't like it, but it's a fact. If you want to make money, you have to make something that isn't free (and even then, if you give away the most valuable parts, as in "open core" licensing, you probably still won't make enough money to make the development worth it).
When I was young and driven by idealism and optimism, I assumed that with enough users I'd be able to ring the cash register somehow. Turns out not so much. We got the users, the money never came. There are a few outliers, but there probably aren't a lot of opportunities to found a Red Hat today.