I wanna say it's for one of two reasons:
1) Being that it never really left in my opinion, most people who wanted more Star Wars are getting it in the form of comics, books, TV shows and more. At most there's been this longing to find out what Rogue One is about and then they finally began giving us trailers and details and whatnot.
2) Is that most people only care about the numbered releases and were mostly excited to see how they'd follow up Return of the Jedi. Fans of all ages could easily get behind that and then just wait until the next numbered release. Kinda doubt most would be interested in a Star Wars movie without Jedis.