Looks like Marten Mickos, one-time CEO of MySQL is leaving Sun. Matt Asay talked to Mickos, and had a sense that they key motivating factor was "(Mickos') frustration at Sun's bureaucracy."
I have no doubt this was a strong contributing factor. I've had my own experiences with Sun over the years, and while I love the technology they produce (which apparently enough other people like to keep them a big company), the business side of Sun can be maddening. Getting something done with Sun is typically a big exercise in patience.
But in contrast to Matt, I don't think the bureaucracy was really it. Though I only know Marten through very casual, infrequent conversations, two things show up for me: