Since the franchise hasn't been rebooted like so many others, it hasn't seem the $$$ marketing that would introduce it to new generations.

Like The Princess Bride or Labyrinth, BTTF currently remains a phenomenom of the 80's and 90's -- familiar to most from that time and deeply treasured by some, but not refreshed and sustained the way the Star Wars, Star Trek, Marvel/DC, etc brands have been.