The message is that our minds have been moved from productive works to finance, to the detriment of society. It's nothing new:
"I'll tell you what I think of the way this city treats her soundest men today. By a coincidence more sad than funnny, it's very like the way we treat our money. The noble silver drachma of old that we were so proud of, and the recent gold coins that rang true, clean stamped and worth their weight throughout the world, have ceased to circulate. Instead, the purses of Athenian shoppers are full of shoddy silver-plated coppers. Just so, when men are needed by the nation, the best have been withdrawn from circulation." Aristophanes, 400 BC
In early 21st century (Margin Call) America, a man like Eric Dale could have been building bridges but instead he's devoted his skill to finance, and indeed just before this story takes a bridge collapsed in Minneapolis. Likewise, the space shuttle had recently wrecked, and her the movie shows us Peter Sullivan in finance instead of rocketry. Society needs these people to improve capital goods, but instead they have been withdrawn from those productive ends and placed into finance, where they make money by trading money, not by creating things which could help 'the nation'. Just as in 400 BC, the once great currencies of modern times have been debased, now just cheap paper or digits created from nothing on computers. The misapplication of human & physical resources at the same as the destruction of the currency, to Aristophanes and the makes of this movie is just a coincidence, but to me it is causal.
Large complex societies need currency not only to make trades of goods and services possible, but also to provide information to the people in the economy to tell them what to do with the resources they have. "The price system" that was described in 'I Pencil' is supposed to encourage people to do the right thing for others, to respect their needs and preferences. But in today's 'capitalism' it sends corrupted information throughout the economy, because it's based on a corrupt currency. It told Eric not to design bridges but to trade fiat currency. It told governments not to be careful how it consumed resources but to expend them on needless wars.
Before I get too political, I will end by saying that this movie is a work of many people's subconscious minds, illustrating more profoundly this phenomenon more than our waking minds ever could. Highly recommend it. The excellent acting, lighting, and gentle humor are bonuses to the meaning.