Dolphin Emulator is open-source, devoid of corporate funding to my knowledge, and does not sell premium builds to my knowledge. I don't think any of the developers can live off their work on Dolphin. However many other emulators do sell premium builds, and I'm not aware of many other open source projects that haven't sold out.
Dolphin's a great example actually, thank you! I think you're right that nobody could live off of Dolphin. I know one of the "active names" has regularly stated that it's a hobby for them. I do wonder how they fund services like https://dolphin.ci/#/ - it's got to be someones passion. But clearly, funded by altruism, a very well deserved exception to my statement.
