I'd say its a combination of the production process taking so much time and the writers being trapped in the "eternal now". Yes the Death Note movie was a, (terrible), thing that was trending on Twitter at one point but by the time the script is written and the show is animated and released, its been two or three years since it was trending and everyone has written it off as crap. That's one strike against these new THOH parody's. The other is like you said, originally they were taking inspiration from the classics that had stood the test of time or they did segments in the style of horror genres, but now they just do what is popular in the public eye. When all you know is modern pop-culture, 99% of it is going to be forgotten garbage discarded from the publics memory when the next shiny product comes on the market. To these new modern writers, things like the Twilight Zone, the Amityville Horror, and Edgar Allan Poe don't exist but Jordan Pelees newest movie is the greatest thing in horror ever made until his new movie is released and advertised as the greatest thing in horror ever made. They're consoomers who only know about current product working on a show that advertises said product eight months after its debuted.