Everything you say is correct. It's trivial to create your own root name server. The problem is in getting anyone _else_ to pay attention to it.
The people who, in practical terms, operate the root name servers are a pretty independent bunch. Regardless of ICANN's nominal authority over them, they're not going to do anything to destroy the integrity of the internet. And that's why it's a good thing that the addresses of the current root name servers are so deeply embedded into so many of the domain name resolvers out there.
-- George Mitchell