Woah, so if Satoshi would go in this direction, would the extant version need to be done away with (legally anyway)? Not at all implying that he would, anyway, just wondering.
No Balthazar is playing academic semantic games.
The code was released under MIT license. Satoshi has no control over either the original copies (unmodified copies of the code he released), or derived copies (improvements to Bitcoin protocol, altcoins, etc). None.
Just to try and confuse the point Balthazar is saying that IF Satoshi could convince every single person who has a modified copy of the source code to delete it (not just Gavin, or every developer, but every single human on the planet who has a copy), and not just every original copy but every derivative copy as well (all the improvements to Bitcoin, all the alt-coins, etc) then he could modify his copy (the only remaining copy) and release it under a different license.
Essentially an asinine scenario which was pointless to even bring up other than to confuse the fact. It would be like saying if I found every single copy of Shakespeare's works and destroyed them. Literally every single copy, everywhere in the world, not a single tattered copy in a bookstore, not any copy on a publishers computer, no ebooks. Litterally every single copy destroyed except the copy I own. I could then modify the copyright page and release his works as my own. How would anyone prove that I didn't write it. Of course that is such a stupid asinine scenario nobody discusses that when covering what a copyright means.
If you download a copy of Bitcoin (or any open source project) you have a right to keep it, modify it, distribute it, publish it, etc. Just like the MIT license says in plain english.
... Permission is hereby granted, free of charge, to any person obtaining a copy of this software ... to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
Nobody can take that right away. Nobody. Obviously like any other right you can voluntarily give up your right but it can't be taken from you.