- The SO was great because answers for noob questions where hard to find. At this point of time (thanks to SO and their knowledge database) there are so many other resources to get these noob questions answered or they are already answered. And some of these other resources are updated to reflect the most recent technology changes while SO answers are static.
- Now people start asking hard stuff - but engineers (I intentionally do not say developers) who know answers on these questions are not interested in answering.
- People who got reputation and they are moderator (they made SO successful) do not know what they do not know.