No one forces people to use v3, and notably the linux kernel will be v2 forever. Market segments have settled against certain licenses, but others don't care. I'm glad developers have choices.
The choice to use a particular variant of the GPL may be an effort to spite companies. Personally I'm looking forward to the next iteration of MS's stewardship of GitHub in the hopes that they add a "buy a license" button so devs can make sure freedoms are protected in the general case but also make money by giving alternate licenses to companies that were never going to contribute anything back anyway but may benefit the common good in some other way.
For what it's worth I'm not entirely sure the grandparent's account on code signing is the issue with GPL on iOS, but I'm not a mobile developer so I'm relying on memory of reading other accounts. My prior belief was that it was simply that the end-to-end process of putting a release build of your app on the app store involves integrating Apple-copyrighted code which they don't want to become infected by the GPL and so they don't allow distributing apps under the GPL. Even though side-loading isn't as easy as Android you can still do it with a developer build, so it can't just be some issue of cloning a GPL repo that's 99.9% shared by an app store app and building and using your version locally...
Advocates for GPLv3 say that the common good includes ensuring that everyone has the ability to obtain and modify the source code to everything they run.
However, others say this actually infringes upon the common good, because it artificially prevents technology from developing and being used, by placing too much importance on the role of technology (and the Perfect Software ™) in the quest for human happiness.
I strongly agree with the second group.
2. The other option does already exist, and that can't be ignored or erased.
3. The second group wins out because most people clearly see that technology isn't the limiting factor in human happiness.