alt Hacker NewsHere in South Africa, we have "Taxis", which are individually owned (to a degree) minibuses crammed full of people. Routes are whatever maximises earning potential for the driver, so it is a kind of bottom up solution in a sense.
It is a violent cartel, so certainly not a good thing across the board, but it's just an interesting variant.
In most countries in South America there is a similar system of buses called combis (or micros). The buses are private and the routes change at the whim of the driver/owner based on demand, etc. Usually main stops are posted in the front window of the bus (it's messy looking lol)