Copylefts only have teeth because of these "stupid" IP laws. Free Software would be nowhere without copyright. (Yes, you could redistribute binaries, but you could not compel the release of source code for derivatives.)
Let's assume the worst. Some company wants to make a photoshop competitor. They don't want to invest too much money into a internally developed project that will very likely fail. They disregard the GPL and fork the GIMP codebase without releasing the source code. Now a few months later they release their software at a $60 pricetag.
Those bastards! They stole all of our hard work to make some money! Now there are two possible scenarios. It will fail because they can't compete with GIMP which can be obtained at a $0 pricetag and respects their freedom. The user can have their cake and eat it too!
That's a pretty tough nut to crack but what if people actually end up buying the software? The only explanation would be that the fork presents added value that is worth paying money for!
In both scenarios the end user cannot lose. They either get higher quality software that suits their needs or software for free that respects their freedom.
Very interesting point which I'm sure gets overlooked quite often. It seems even Richard Stallman is in favor of preserving the idea of copyright (albeit reducing its duration), which came as a bit of a surprise to me given his otherwise radical views: http://www.computerworlduk.com/blogs/open-enterprise/could-f...
Well one interesting thing about Stallman's "radical" views is that, unless I'm missing something, he doesn't actually advocate any kind of governmental action or laws to support his views (aside from shortening copyright duration as you mentioned). He wants people to voluntarily demand and require Free software; he never talks about having the government force it on people in any way.
Now contrast this to many other people, including the people in favor of stronger IP law, who want the government to enact their views into law.
Now what's really bad is that Stallman is the less pragmatic and realistic of these two camps, because he wants regular people to "see the light" and voluntarily subscribe to his views, which obviously isn't happening (he's been at this for 3 decades now, and while Free software has made traction for sure (e.g. Linux kernel in most smartphones and many other devices), users seem to have less real freedom than ever thanks to locked bootloaders, app stores, etc.). By contrast, the jerks who want to force more DMCA-style silliness and even lengthier (effectively perpetual) copyright terms are more realistic because their approach actually works: we have or are getting all these bad laws.
This somehow reminds me of the quote by Shaw about all progress depending on the unreasonable man.
I'd argue that you don't need the whole set of "IP laws" that are being complained-about, in order for free-software to function correctly. IP law has grown into a gigantic hydra monster.
Those bastards! They stole all of our hard work to make some money! Now there are two possible scenarios. It will fail because they can't compete with GIMP which can be obtained at a $0 pricetag and respects their freedom. The user can have their cake and eat it too!
That's a pretty tough nut to crack but what if people actually end up buying the software? The only explanation would be that the fork presents added value that is worth paying money for!
In both scenarios the end user cannot lose. They either get higher quality software that suits their needs or software for free that respects their freedom.