You are restating what I said in my first paragraph -- yes, if they are the sole copyright holders they are not bound by the distribution rules of the GPLv3 in the same way as everyone else -- even if the GPLv3 did attempt to restrict the original author, as sole copyright holders they would be able to ignore the provision anyway.

I still don't agree that this is in the spirit of the GPLv3. In my view, the binaries at least are under a proprietary license.