Earlier quoted context omitted.
The AGPL doesn't guarantee that you'll get contributions back. For the very few companies who are willing to touch AGPL code, they only need to make the changes available (e.g. a CD in the post is sufficient). Very few companies are willing to use it, because it creates an almost unassailable hurdle in lots of industries. It's also highly at risk at making a bunch of other projects AGPL as well.
It does nothing of the sort. This is propeganda that mega-corps want you to believe because they are unable to rip off AGPL software effectively. Organizations like Google can afford to not use AGPL software (they can just write their own software), but it costs them money, so they refuse to use AGPL software and spread propeganda that it's impossible to do so, to weaken its market penetration and ensure that they ha…
That is incorrect, the modifications have to go to users not upstream. All the GNU copyleft licenses are like this.