Play writes and song writers love new ideas. In the case of music, statistically, the audience prefers songs that they hear often. A very similar effect happens for movies. Not knowing which movie is best, the audience goes for the sequel in preference to an original movie.
When scaled, the consequences of this decision suck. If you listen to music infrequently, the new Tayler Swift song sticks out in your mind. It's the same rhyme structure lyric repeated over and over, and the repetition makes it memorable. However, if you listen to music regularly, top 40 music quickly becomes boring and repetitive, because it is mind-numbingly repetitive.
The same happens for movies. Sequels come out on a roughly two year schedule. If a casual movie goer sees two movies per year, then the sequel will seem new and different after about two years. If you see lots of movies, then the sequel looks very unoriginal because you have seen so many variations on the same concepts, special effects, writing, directing, and photography in the intervening time.
It could be argued that two movies per year is rather few for the modern American movie going audience. In terms of theatre revenues, this is probably true. However, Hollywood makes movies for the world audience. In a world that mostly does not speak english, then it is vital to have simple script writing, very easy to understand plots, and assume that the audience will only see a very few movies per year.
Play writers and song writers see lots of movies and songs, and they often dislike these limits on their creativity ...
