I think all these points have contributed to the decline. I have rarely posted in the last few years. Partially because i didn't like the new format, partially because a lot of the individuals I knew better had started to drink less, so also post less.
It would be nice to get a good boost here. But, I also think we would need to be more accepting of newer members. For a while there, anyone with a basic question would be torn apart for either not searching the forums first, or asking a such a simple question.