This question seems based on the presupposition that SE > Forums for all things.
That is not and has never been the case or intent with Stack Exchange.
There are certain things that the Q&A format does much better than a forum. But there are some things you simply can't do in Q&A. Every day, we get questions on SO from people who have no idea what they're doing. Who are just starting out and ask nonsense, basic, or just "help me" questions. These are quickly downvoted and closed. As they should be.
But that doesn't solve the problems of the people behind those questions.
Q&A sites are a way to use the question/answer format to create a knowledge-base. It's designed to be impersonal and clinical. That's great, for that purpose. But one thing it isn't is personal help. It isn't guiding a person, step-by-step, through the initial steps into a piece of technology.
So long as people need help, they will need something other than Q&A to get it. Forums help people. Forums are personal. Forums are a decent means towards providing someone with help.
Forums are still useful. To me, the most important thing that the SE model does is get Q&A off of forums, so that forums can do what they're supposed to: deal with personal interaction.
That's not to say that the Tridion developers shouldn't push SO as a useful place to ask real, practical questions. But that doesn't mean that they should just hang up their forums.
Don't be too proud of this technological terror you've constructed.