I believe it's the story of submarine patents. Ogg is not developed by a large corporate entity, so if anyone has a patent that it might break, it does not pay to sue anyone. However, even if the owner doesn't care about OSS users and is dormant, Nokia might be a tempting target to aim for. As Nokia had no part in development they can't guarantee/verify that ogg is really-really free for them to use without risks. I hope this makes sense.