Actually, if you care to examine the GPL, while it's not imposed - it's actually fairly heavily implied.
People all around the world write FOSS code. I do it too, sometimes, though of recent times I've deliberately put a non FOSS, but custom freeware licence on my work to prevent certain ne'er-do-wells using my work.
Here's the thing. I'm in the position I can produce stuff for free and give it away. Many others cannot. If I were working as a paid developer, I don't see how I'd be able to use the GPL, and this is the problem with it.
The GPL only works in the ideal world, where people can create code without financial recompense from their work. Because you can't charge for GPL stuff, you just can't. The licence explicitly demands that anyone who makes use of your work and then distributes it themselves (be it as a library or something else), has to release the work under the same terms and freedoms.
The best example I have of this is MySQL, actually. MySQL's a GPL product. You want to build something based on MySQL and sell it? Well... you can use the GPL version and sell support, or you can pay the licence fee to get a non GPL version. That's the part most people seem to conveniently omit.
Now, you're mentioning that fact but you're glossing over the fact that it's inherently a *dual licensed* piece of work at that point. It's not GPL at that point, by definition, or least the use the company gets out of it isn't GPL'd at that point.
Anyway, I think you're still missing the point. The reason why GPL is noticeably absent from the store is the requirement that it would actually make the store hard to enforce (and I note that Apple has similar restrictions actually)
There is, noted, an exception in the GPL for system software, in that you can link to system software that is not GPL in GPL software and that's allowed. But you can't use it to link to non-GPL components without the combined work as a result being GPL. Which does put a dampener on anyone using various paid frameworks to release GPL software.
It's actually easier for them to simply deny GPL software and avoid the inevitable fallout that will go with it because as distributor, if a piece of software is found to have GPL code that isn't being used correctly, they're the ones who will ultimately be immediately (if not finally) liable.