I agree with some other commenters; this is a lot of cherry picking. You could just as easily compare Nosferatu (1922) with Blade (1998) with Twilight (2008) and ask why culture gets happier and less serious as time goes on, “aren’t we all becoming like Brave New World???” Comparing Adam West’s Batman with today’s Batman is just lazy. They’re apples and oranges at this point: different genres, different climates (today the more “fun” stuff is Marvel), different film technology. And if we want to get into it, it’s not “depression” that’s trendy; it’s realism. 60’s Batman dealt with all the same “dark” themes as current Batman: mafia, crime, trauma and grief, etc. But the visual portrayal was different because it was a “comic book” before comic books adaptations were commonplace blockbusters. That doesn’t mean all of 1960s cinema is somehow a comic book movie. Hello: Psycho (1960), Dr. Strangelove (1964), The Good, The Bad, and the Ugly (1966).