Shoe event horizon 

The Shoe Event Horizon is an economic theory that draws a correlation between the level of economic (and emotional) depression of a society and the number of shoe shops the society has.

The theory is summarized as such: as a society sinks into depression, the people of the society need to cheer themselves up by buying themselves gifts. This is usually done through the purchase of shoes. As more money is spent on shoes, more shoe shops are built, and the quality of the shoes begins to diminish. This makes people buy more shoes.

The above turns into a vicious cycle, the end result being that other industries begin to falter.

Eventually the titular Shoe Event Horizon is reached, where the only type of store economically viable to build is a shoe shop. At this point, society ceases to function, and the economy collapses, sending a world into ruin.

The population of the planet Brontitall was forced to evolve into bird-like creatures in order to survive the result of the shoe event horizon.

Shoe event horizon by Kakapo March 27, 2009