The 3 franchises you named share common traps—each franchise began with a fairly straightforward 80’s action film. Terminator and Alien succeeded in part because of all-time greats writing and directing. Arnold being Arnold is what made Predator so rewatchable.

James Cameron had unpredictable creative visions for T2 and Aliens. But that’s where it ended. The flaws in the subsequent installments are the same as for Star Wars—no universe bible outlining a coherent vision. Instead it’s just movie studios throwing money at IP to drive corporate earnings.