My former student Dan Alban points me to a WaPo article on sidewalk food vendors in DC. Apparently a long time wholesale supplier of vendors is facing some new competiton from Zipcar entrepreneur Gabe Klein. The article details the back and forth between WG, a firm that has held a large share of the market for years, and Klein. While it is amusing to know that WG's owners refer to Klein as the backpack guy and Klein refers to WG as the hot dog guys (because their carts peddle hot dogs instead of more modern fare such as hummus) the article completely misses an obvious question--why has WG held such a large market share for so many years? Could it be that, just maybe, there are some provisions in DC's complicated regulartory regime that created frankfurter monopoly? That's my bet, but the article contains only the vaguest hints.