Bzzzt wrong, Any given weekend there is a Star Trek or Dr Who convention somewhere in the US and World, The movies capture a small segment of the fanbase. Heck there are even Hollywood quality Fan Fiction Star Trek movies being released with Paramount's approval.
http://www.startrek.com/fan-films
I can't even imagine Disney doing something similar but Disney DOES work hard to marginalize organizations like the 501'st Legion, Yeah There is a great idea, crap on your franchise's biggest fans.
Same deal for Doctor Who, BB-8 meh' RC Dalek - TAKE MY MONEY!