There's still the cost of managing it (you're looking at $millions) - it's something that various parties have looked into, and then decided against. It's also

There's still the cost of managing it (you're looking at $millions) - it's something that various parties have looked into, and then decided against. It's also unclear that having a third-party holder would actually be any better. So far Microsoft have behaved far more reasonably than you might expect, and what problems there have been can be chalked up to large company rather than malice. I understand why people don't want to trust Microsoft, but I don't currently see any evidence that they're misusing their powers here.