Open source software is an interesting example, but I think it mostly supports my case.
If you look at the projects out there, you can divide them into roughly 3 camps.
1) Projects that have a lot of paid developers working for companies or organisations that pay wages to their developers. So stuff like Android , V8 and Ubuntu would fall into this camp.
2) Projects that people were not necessarily paid to develop , but were developed mostly as a biproduct of something that they were or as a way to do that thing more effectively. "Scratch an itch" software effectively. I guess something like RoR would fall into this category.
3) Pure passion projects that were developed for fun. This is the only group that is purely intrinsically motivated.
The thing with projects that fall into camp #3 is that they tend to be stuff that the developer themselves found useful or interesting rather than something that necessarily serves society at large, though the two may sometimes intersect there is no guarantee.
If you don't make peoples incomes at least somewhat dependant upon the software they develop you will see far more camp #3 projects than camps #1 or #2.