The theories presented by Arrow and Debreu were based on an assumption of market equilibrium that stands in opposition to much of the empirical evidence the markets provide us with. Modern behavioral finance theory attempts to study markets under states of non-equilibrium.
Debreu won the Nobel Memorial Prize for this work in 1983. Since Arrow and Debreu's work was first published, the prevalence of financial derivatives products has grown exponentially.
Investment dictionary. Academic. 2012.