You say that like it is some force of nature. Movies don't have to be expensive to make and Ebert specifically called out that the bright spot for 2011 was independent films.
You are correct about branding, but the movie studios decided to make these big budget movies. They are gambling big for a big payoff when they certainly could make great movies significantly cheaper.
I bet if you looked at studio executives' compensation packages, you could draw a link between their compensation and the 'go big or go home strategy'. I would bet they make a lot more money in bonuses if the studio has a huge year than one with good year over year growth. Add that to very little downside if they create flops (just blame the pirates!) and you have a recipe that likely explains the current behavior of the systems. Just a guess.
You are right that movies don't have to be expensive, but I do believe to get the kind of revenue that the big studios want, the studios believe the movies need the big name actors, the explosions and special effects, and 3D. The indies and docs were a bright spot in terms of enjoyment for the movie goes, but I do not know whether the studios believe they are a bright spot or not.
You can actually get decent effects and explosions these days for "cheap". District 9, one of my favorite Sci-Fi movies, had a budget of $30 million and was amazing. If they made movies around that size, they would lower their risk profile, while still having enough effects punch to make a blockbuster.
If they did not play accounting games they could pay actors based on movie revenue without increasing upfront costs. However, major studios are setup as cost plus contracts where they get upside on successes and still make money even if nobody sees the movie.
Also, if you look at the actual costs it's not hoard to find advertizing more than 50% of the budget for mildly expensive films. Because advertizing is effectively a huge fixed cost they are incentive to make expensive movies with big stars and or explosions that they can leverage to make their advertizing less expensive.
EX: Jurassic park and Avatar could show Dinosaurs and so did not need big name talent to get people into seats.
You are correct about branding, but the movie studios decided to make these big budget movies. They are gambling big for a big payoff when they certainly could make great movies significantly cheaper.
I bet if you looked at studio executives' compensation packages, you could draw a link between their compensation and the 'go big or go home strategy'. I would bet they make a lot more money in bonuses if the studio has a huge year than one with good year over year growth. Add that to very little downside if they create flops (just blame the pirates!) and you have a recipe that likely explains the current behavior of the systems. Just a guess.