You're forgetting one of they key points of buses in dense places: Parking! Here in DC I can out-drive the bus on any route in the city, but when you factor in

You're forgetting one of they key points of buses in dense places: Parking! Here in DC I can out-drive the bus on any route in the city, but when you factor in 20+ dollars/day for parking downtown, or spending 30 minutes finding a street spot, the bus wins hands down.