FSM is about making all software free, not all software GPL'd. If copyright laws are dissolved and prop. software got outlawed, there would be no need for GPL. GPL is a hack to circumvent future prop. software using your code. In other words, if no one can hide their source code, there wouldn't be a difference between MIT and GPL.
Abolition of copyright and banning proprietary software seem like two very different things. The comment I replied to just mentioned elimination of copyright. I agree that combined with a ban on proprietary software none of the licenses would really matter - depending on the wording of the laws of course.
While having the source is an important part of something being free software, the far more insidious problems with proprietary software are the other freedoms they strip away from you -- the freedoms to use and distribute the software.
Not to mention that in the 60s, source code was always provided because nobody thought it was valuable (and copyright was not applied to said source code). The software was the source code. I can imagine that if we actually went through a cultural shift of abandoning the completely ludicrous views of modern copyright, that companies would start providing source code again (we're seeing that happen today, in small steps, with companies making more and more free software projects -- even without the copyright reform). There would be no incentive to keep the source unavailable, because they'd have no monopoly on it.
