The problem is, even in a city like San Francisco, that's relatively densely populated AND has a centralized office area - there is A LOT less overlap than you'd think.

The typical bus already runs at loss of 4 dollars for every 1 dollar it takes in in fare.

So you're not going to end up with a much cheaper ride than if you just took a private taxi, but you're going to have a significantly longer trip.

Almost no one is interested in that.

I hope to be proven wrong.