It’s when it’s ready for a reboot! I strongly associate it with the movie industry running out of new ideas after the 90s. Episode 1 was 1999 for example, before that most people thought Star Wars was over. Then the marvel stuff.

But maybe that’s just me being nostalgic since that’s also around the time I began being an adult. It does seem convenient how it’s usually timed out so that parents can geek out with their kids; so the industry inherits a new generation of fans. My recent example of that is how apparently Pokémon is very popular again. I was too old to care in the 90s but those kids now have kids of similar age as they were at the time.