Slate’s take.

With all these new agents swarming onto the scene, the price they charge may remain constant, but the number of houses each sells will not. The zero-profit condition predicts that, in locales where housing prices rise, the number of agents will also rise, and acquiring new clients will become that much more difficult. The occasional star agent will always make a bundle. But the theory suggests that the average agent won’t make much more in places where house prices have risen than in places where they haven’t. (HT – Curbed)

‘Nuff said.