Your own client work, etc. doesn't have the same requirements for graphics and CSS as WordPress themes because the work isn't distributed.

The foundation holds the keys to the WordPress logo, and it also does things like support WordCamps that aren't profitable to keep those communities strong. It's also a legal barrier to protect WordCamp organizers. See this post: http://wordpressfoundation.org/2012/wordcamps-and-such/ The foundation is also starting to monetarily support local meetups (more frequent gatherings than WordCamp). I think Matt is the only person in charge of the foundation, but I'm not sure.