None of these ideas are my original thoughts. I'm paraphrasing a bunch of other folks.
Similar things happened to music in the 1960s and movies in the 1970s. The old system had fallen apart and no one in charge had any idea what to do. The only thing they could think of was to throw cash at anything that moved and hope for the best.
That's why in the 1960s you could have bands as diverse as Frank Zappa and Bob Dylan, and Sha-Na-Na and Iron Butterfly etc etc all getting a chance. They guys [it was 99% men] who understood Sinatra and Bing Crosby just went with whatever the kids seemed interested in.
Same thing in the 1970s with movies. 'Star Wars' was a giant gamble, but the studio heads figured they had to try something.
Cut to today. Entertainment industry has figured out how to keep the machine moving. We'll keep getting Taylor Swift and Marvel movies until the next generation stops paying.
Dunno man, probably very important world and character building
Srsly tho, I think the biggest prereq to these movies is watching the horror films they riff off of. I was very confused in Scary Movie 2 because I didn't see half the films they referenced.
