because like flash gordon which these movies were based on the hero never dies.
even the villains don't stay permanently dead. as ming rose from the dead in flash gordon so did the emperor palpatine in dark empire.
i think people try to make the movies look serious when they were made for ages 5-9 and are kiddie fare.
like the transformer cartoons unless looked at through rose colored glasses of nostalgia don't hold up to the mind of people in their 20s or 30's, hell even some teens find the films laughable or contemptible. still they are worlds better than the prequels, just like buster crabbes flash gordon is better than the new sci fi version.
the new jedi order was the first star wars series to try to add some adult and real world things to star wars like death, and non black and white characters i.e. ambiguity. the prequels did this also but rather poorly, similar to how poorly the legacy novels are being handled.
as to whether the oot is relevent to the time in which we live, post 911, in comparison to say the new battlestar galactica is a discussion for another time.