As I said in another reply, a one-way trip to the downtown area of my nearest city is a 1.5-2 hour trip, making for a 3-4 hour round trip commute. This is because the first bus I'd have to catch meanders through the suburb, stopping often, because that's the only way to provide service to giant spread-out suburbs. Either that, or you'd need like 3-4x as many buses cruising through neighbourhoods that were not designed to accommodate buses. And that's not remotely politically viable.

The bus I would catch is usually mostly empty. People don't bother walking anywhere from 5 - 30 minutes to the bus stop to take a 45 minute bus ride to a place that would've been a <15 minute car ride away. And they do have a car, there'd be no realistic way to live in a suburb without one. And most people live in a suburb.

Frankly, typical American suburbs aren't really dense enough to support bus routes. That's why it seems to me that something like this could work. Dynamic bus routes that come closer to your actual home and take you to a trunk route in a reasonable time would be very handy.