While Apple isn't 100% open source, they are the closest among commercial end-user targeted OSes. Apple obviously feels, and honestly I think they're probably right, that fully open sourcing their OS would negatively impact their ability to run a profitable hardware/software business. That's absolutely their right.
I'd also argue that for mass consumer end users, there is no open source revolution. While I love and use Linux all the time, I'd never put my mother or my sister or my wife on it. Likewise with software, it needs to come with a nice printed or online manual that's easy to use, and a 1-800 number for the support department. Fixing an issue needs to not involve steps like "use vi to edit giant.xml which depending on your distro could be in one of these 10 long path locations".
goes to get coffee