Even if no VC was involved, how do you make money developing an open source linter?
Clearly the creator of ruff is going to expand from an open source tool into a company focusing on Python tooling and developer experience, services, etc. There is a market for stuff like that just based on pycharm and jet brains' success in the space alone.
All this while remaining a team of 2-3, hopefully, with all company-running stuff minimized and outsourced.
But you might be able to do support contracts, like ansible. Tough road though.