Hello! Author here. Quick responses:

1) With superior scale, the utilization of each Waymo approaches 100%. "Empty rides" going to a new pickup spot become more and more rare because they immediately get a ride close-by.

2) I think you underestimate the case for shared rides. Any Waymo with >= 2 passengers is reducing congestion, not adding. When you consider small bus-shuttles, e.g. 6 or 12 or 18 seats, it gets even more impactful.

3) The point with suburbs is that they become more accessible when the price point comes down. If you have a 45-minute commute to drive yourself, an Uber might cost you $60, which would be prohibitive. If a seat in a carpooled Waymo costs only $5 or $10, the incentives and customer behavior change significantly.