That's a really good point. There definitely are shades of gray. There are companies where one can have a voice and build some great things. One doesn't have to be the founder to be part of an entrepreneurial effort.
It doesn't always always have to be about money. Open source software gives people to build something, break some new ground and make a change. I guess that's the same drive that gets people to found or be part of all kinds of efforts that extend beyond software and startups.