The great thing about a movie is that it can be about literally anything. Hollywood might be trying to sell us an increasingly narrow range of franchises and blockbusters, but it only takes a little bit of thinking outside the box to come up with something truly wild. It doesn't even have to be a highbrow, art house thing, either. Sometimes, the best ideas are a little bit of random inspiration mixed with all the tropes that we know and love. Unfortunately, the films that hit this sweet spot are few and far between.
Still, it doesn't mean that we can't dream about them. Anybody with some pop culture knowledge and a touch of creativity could think up some movies that are a better idea than anything that gets approved by an exec nowadays. For now, they may only be contained to these fake posters. But who knows? Perhaps they're the next big thing.