Ever since Disney paid $4 billion for the Marvel franchise in 2009, their movies have been making less and less money. What’s going on? It turns out the problem has been baked into Marvel’s writing culture from the start. The old fashioned “Marvel method” of writing comic books has the writer provide a summary of the story to the artist, who then draws the entire issue. When the art is complete, the writer goes in and adds the dialogue.

Lately, Marvel Studios production has worked more and more in the same way. Production will start even if the script isn’t finalized, and the filmmakers, like the artists of Marvel comics, are expected to fill in the details while they’re shooting. As you can imagine, that’s financially risky. Every second on set for a blockbuster production costs millions of dollars, so waiting around as the directors or actors or on-set writers try to figure out what should happen next causes budgets to balloon.

As the budgets rise, the margins for profitability become slimmer and slimmer. “Captain American: Brave New World” cost $300 million including marketing to make, and made $415 million worldwide. “Thunderbolts” cost $280 million including marketing to make, and made $380 million worldwide. The two movies are being described as “flops” by industry commentators, and the trend seems to only be getting worse as cast members of “Avengers: Doomsday” report that they don’t know who they’re in scenes with because they were shot individually on green screens so that the directors can piece scenes together later. No wonder the upcoming crossover movie was delayed from May to December.

Director James Gunn watched this happen first hand when he worked on the “Guardians of the Galaxy” trilogy for Marvel, so it’s no wonder when he launched DC Studios with Peter Safan he instated the rule that no project will start production until there is a finished script everyone is happy with. “Superman,” for example, made $614 million worldwide for DC Studios against reported production and marketing budgets between $200 and $300 million. The simple lesson seems to be that you want to prioritize good writing before you begin production on a big-budget movie. But will Marvel’s owner, Disney, ever learn?