There is some long-standing and valuable knowledge here also which aids it, although I feel that of late this is diminishing.
I would agree with your first point, though do hope you're wrong about the second. I haven't posted much until recently (had little to add!) but have lurked for a while, and have been the beneficiary of the wisdom you mention. I hope that it isn't declining, and that the many knowledgeable contributors remain active.
On a personal level I find both the knowledge and the wit to draw me back. Often, the way that knowledge is imparted via the "British sense of humour" (and understatement) on here can be highly entertaining...