Sure, there would be software with code not published, but if it was ever leaked which it often is, you could do whatever you want with it.

But in a world where copyright does exist, copyleft is a tool to fight back.

And then if we can close that loop by taking their proprietary software and feeding it into a NN to re-liberate it isn't that a net win for software freedom?

Today crossing the sourcecode->bytecode veil effectively obfuscates the implementation beyond most human's ability to modify the software. Humans work best in sourcecode. Nothing saying our AI overlords won't be able to work well in bytecode or take it in the other direction.

I guess what I'm saying is, today a compiler is a one-way door for software freedom. Once it goes through the compiler, we lose a lot of freedom without a massive human investment or the original source code. Maybe that door is about to become a two way door with copyright law supporting moving back and forth through that door?