The issue is trust. I don't mind paying for closed source software one bit if I can run it in a sandbox with extremely limited privileges and network access on

The issue is trust. I don't mind paying for closed source software one bit if I can run it in a sandbox with extremely limited privileges and network access on an opt-in basis. But a remote desktop solution isn't useful that way. By definition, it has to have all the powers that you have. And for that reason, it's one of a very small number of categories of software for which closed source is simply a non-starter.