And then you get fan stuff, which takes the concept of a throwaway pop culture reference and expands it beyond all sense of restraint to stealing entire scenes from movies and repeating the script word for word, as the Nostalgia Critic has been doing lately. Lifting five minutes of dialogue from The Search for Spock without adding anything original (beyond the production values of a school pantomime) IS NOT FUNNY. The sequence itself is boring because you know exactly what is going to happen, so then pointing out that it's a reference, when we'd worked that out ourselves five minutes earlier because it's one of the most iconic moments in the history of SF movies you are making a shabby copy of is also NOT FUNNY.
It doesn't help that the majority of these in jokes are referencing the same old classics that everyone else references. Entire generations have grown up knowing the original Star Wars movies, not from watching the films, but from seeing choice bits of the script endlessly recycled in everything from kids' cartoons to political satire.
It reminds me of the story about Jack Kirby, who read an interview with some new guy on the CAPTAIN AMERICA comic. The new guy said he wanted to produce CAPTAIN AMERICA "in the Kirby tradition."
Kirby grunted and said, "This kid doesn't get it. The Kirby tradition is to go create a new comic."