vs.
"I feel like writing a high performance, multi-node key value store, just to prove that I can" OR "I enjoy coding with X, and I think I could make a really cool browser with it" OR any other number of motivations.
Some of those motivations produce a Redis, a guiding principle, a community, co-developers and a market. Some of the produce a SourceForget project that is never heard from again, let alone improved beyond alpha quality.
But that's a lot of flowers blooming, and there's no shortage of developers realising that FLOSS is where the action -- and practical education! -- is.
DVCS and social coding venues like GitHub make it all the more easy to start, share, and improve.
You'll probably see all of that as messy and inefficient. Most experienced FLOSS developers see it as a necessary by-product of open learning, development and innovation -- our process.