I spent the weekend at Finncon in Helsinki. Attendance was around 15,000; the average age was probably under 20; the majority of attendees were female. Yes, this was mainly an anime crowd, but there were also many SF fans there as well. Panels featuring George RR Martin and Al Reynolds were packed to bursting.

No, fandom is not dying, but some people would rather pretend that it is than admit that being a fan no longer makes you a member of a small, persecuted minority.