Author of the article here. It's a bit more complicated for both the driver and the seller.

Drivers have to coordinate pick up and drop off of passengers, which is a pain, especially in LA. On the other hand, passengers getting dropped off can also be a huge benefit since the bus stop probably isn't your final destination.

In general, Europe is denser (more cities within a closer distance), gas prices are higher, and people are maybe more trusting of strangers.