How does a movie cost $100 or $200 or $250 million?
You think they were still using film with silver in it.
There are lots of reasons. One is that movie and television production is a high wage industry, even on a non-union production.
Another is that while technology advances have made the product better — you can get a camera at Best Buy good enough to shoot a TV show — you still need two skilled operators to use it. The cost of that labor and the basic size of a crew never goes down.
Also studios have enormous overhead. The costs to run them are spread out over every single movie and TV show the studio produces. That comes right out of the budget for a given film.
Marketing a film isn’t visible in the final product, but it’s incredibly expensive, and comes out of the film’s budget.
Comic book films are expensive because they rely heavily on computer effects. Effects are cheaper to do on a computer than they used to be... But they take a long time, paying high wages to skilled operators. You can shoot a film in a few months; you can be in post production making guys fly for a year or two.
There are lots of reasons for films costing a hundred million dollars, but those are some of the big ones.