You're correct on the facts, but I disagree with you (and RMS) on what the
end of copyright would cause, for a couple reasons:
1. Copyright would go away one country at a time, and proprietary software is
exploited in multiple countries in most cases. So companies would still have
to follow copyleft licenses to be safe until they no longer have force in all
jurisdictions they are interested in. This wouldn't have a substantial
long-term effect, but it would have a minor deterrent effect.
2. Without copyright, proprietary software developers will have to go to
efforts to make sure that the EULA must be signed for someone to use the
software, that no minors ever use the software (because minors are not bound
by the terms of contracts that they sign), and that the EULA actually counts
as a contract, because otherwise, people would be able to legally
redistribute cracked versions of the software (and would choose to do so),
destroying their business. Proprietary software development as a money making
model would not be able to thrive in such conditions.
3. There are many programs that are proprietary only because of the license
of their source code. Removing copyright would correct that. For example,
almost everything in my article The Gaming Trap would become obsolete. That
would be fantastic!
4. Even without source code, there are cases where people can learn to
competently improve and modify a program. For example, ScummVM has extensive
documentation on what the Sierra Creative Interpreter's object code means and
ScummVM even applies patches to these games; you can see them in ScummVM's
source code as hexadecimal numbers followed by comments explaining what they
do. Then there's the possibility of disassembly, where while you can't e.g.
return a program to its original C code, you can generate assembly code that
has the same result and derive it into workable source code, which can be
useful if an emulator is an option (as with a lot of old game systems).
With all of these put together, I think the end of copyright would be a
massive net gain for libre software, especially for libre games. Sure, there
would be some long-term loss of strategic dominance, and using copyleft while
it has legal force is important, but I don't think this loss will be anywhere
near the long-term gains of making the proprietary software model
unsustainable and removing licensing barriers to making libre programs
(especially games).
