It's not simple to just use buses and change all the regulation for cities to mass-adopt buses. Buses cost a lot of extra time in waiting and slower speeds, are

It's not simple to just use buses and change all the regulation for cities to mass-adopt buses. Buses cost a lot of extra time in waiting and slower speeds, are often much less comfortable, require people to walk further on both ends, are less good in bad weather, and let's not forget: they are very infrequent on holidays/evenings, where we want less drunk driving but fewer buses will be on offer. Buses are a good tool, especially when they're full of commuters, but they can't replace all the benefits of a ride-hailing fleet. Nor will they - many people, myself included, simply prefer to pay more for a taxi/lyft/uber.