As someone who has spent many hours hacking on open source software, I'm not sure I'd call it 'abundant' in that the production of said software is very much a costly endeavor. Once it's out there, yes, it's non-rivalrous, but that's a different thing.
You're going to get some FreeBSD (and other *BSD) users riled up with that one (Hotmail and Yahoo, for example, are too notable services that did - in Hotmails case until well after the Microsoft acquisition - or do - in Yahoo's case - use FreeBSD extensively)
As someone who has spent many hours hacking on open source software, I'm not sure I'd call it 'abundant' in that the production of said software is very much a costly endeavor. Once it's out there, yes, it's non-rivalrous, but that's a different thing.