I would say there are more balanced dogs out there than you think. I think you hear about the nut cases more because they are more dramatic. My female is quite boring. She has zero drama. Not dog aggressive. Not fear reactive. calm around town and in the presence of strangers. Take her to IPO and she fires up nicely then leaves the field with no fan fair. I think a lot of dogs are that way and you don't hear about them because there is really nothing of note to talk about.
I do think those involved in IPO tend to see it the way you do but you are surrounded by people who are training regularly and have the ongoing help of others.
In thread after thread we hear the problems. Reactive, lunges, barks at everything, hides behind me, hates other dogs, doesn't like people, is not good around kids and then there are the health threads.
I see issues with GSDs in public all the time. Matter of fact I've never seen one in public that I would have wanted. Some of it I'm sure is the way the owners handle and do/don't train but a good portion must be genetic.
When I was growing up about the only seeing eye dogs anyone ever saw were GSD. Very few now.