They're obviously selling computers as fast as they can make them. Locking down an interface on said computers doesn't seem to be protecting their core business; it seems to limit the usefulness of their core business. And make no mistake: I want them to survive and continue to churn out very cool products.
I just want a really high-quality (even if "only HD") camera, which would cost much more than what the Pi Foundation is targeting. I don't think it would cannibalize sales from anything they're trying to put out.
The Arduino ecosystem seems to have survived being truly open, hasn't it?