Lots of companies hire people to work on open source projects. It is how most of it gets written. He could probably get a job where working on this is part of it in a heartbeat.
(not that I disagree with this project or method, I think he should do the same as what Google Appengine does with its installer - it is seriously awesome)
Though I'm quite thankful Engine Yard chose to fund his work, I'd categorize doing so as an investment than a generous act. Nothing wrong with either, of course.
I would certainly agree (especially his work on Merb, since they began offering commercial Merb support and such while he was doing that). The "generously" was partially true, partially facetious. :)
(not that I disagree with this project or method, I think he should do the same as what Google Appengine does with its installer - it is seriously awesome)