@PLEASEHOLD they’re doing new Indiana Jones sets…
If you’re referring to the gap between the new ones and the old ones, I think it’s simply a case of marketing. Star Wars has constantly been churning out new content for years, so it’s always present/relevant in the public eye and particularly to younger fans. Indiana Jones, meanwhile, hasn’t had anything new since Kingdom of the Crystal Skull, the installment that-as far as I’m aware-most fans would like to pretend doesn’t exist. As far as Lego goes, its release did afford Lego an opportunity to release sets based on the older films. But once the hype was over, Lego shelved the theme.