[breput]

Rental car companies do not need to either pay for the labor or the fuel to power their vehicles, and actually make a lot of extra money with "prepaid" or "return it empty" schemes. By churning their vehicles on a regular basis, they avoid many of the ongoing maintenance issues that would impact Waymo with their customized vehicles.

You're right that a Waymo would probably outsource the interior and (probably) mechanical maintenance to local providers, but they would need to deal with that in every city and with the additional technology involved in self-driving, you're probably not going to trust that the local shade tree mechanic will be able to handle that. So you have at least two problems now.

Over The Road drivers do make surprisingly good money, but that is a skilled job with a significant amount of training and regulation. In-town cabbies are often people with few other opportunities and are easily exploitable. The taxi cab business is notorious corrupt and is a big part of how Uber/Lyft could easily replace these services.