We do contribute and are very proud of it !
http://hg.nuxeo.org/opensocial is all about our contribution to Nuxeo from Leroy Merlin.
Ok, i doesn't generate a cent of revenue, but it doesn't really costs more. And when people will contribute to our code (patches, bug fixes, extension), this will be code that will cost us nothing.
Moreover, our contribution is now included in the core feature of Nuxeo, so now we will benefit of a vendor certified integration of our code.
