There are also platforms for which the GPL is simply unusable. Quite a few embedded platforms that are tightly controlled by vendors, like the iOS platforms, or the XBox.
While the GNU proponents of course argue that these platforms simply shouldn't be used, the reality is that for many of us those platforms are key and we're rather the entire GNU project die in a flood rather than give up on supporting platforms that over 90% of our target userbase owns. I mean, I'd prefer that the platforms were more open myself, but supporting them is simply vastly more important to my personal and professional interests than in supporting GNU. Permissive licenses allow an entirely FOSS project to be released for FOSS-hostile platforms, while licenses like the GPL ensure that those mega-popular platforms will only ever include mega-proprietary software.