That's a great question, Jane -- we're having that conversation internally right now. If we formally support licensed content, CC will almost certainly be among the supported licenses.
On the other hand, we may want to abstain from delving into the licensing morass altogether, and instead focus simply on the simple mechanics of open-sourcing educational material. GitHub for example doesn't formally support licensed code (as a feature), but provides a reference site for those wanting to include explicit licenses and even makes the process of including a license _file_ very simple. This means the license lives with the code itself, rather than with GitHub (as a feature / attribute on the data), which may be preferable.
What would you like to see?
The political landscape of the publishers and the institutions is a challenge, but I think you're right; we've reached a point where the system simply cannot sustain this level of systematic incompetence any longer. Something has to break, and open source is going to rush to fill the void.