Some people need to live in "the sticks" to produce the resources (food, ores, oil, timber) that the rest of society relies on. Subsidizing the availability of services for those people doesn't seem unreasonable, and it is certainly something the federal government has historically taken responsibility for (for mail, electricity, telephone).
Why not just let the market find its own equilibrium? If people need to live there to produce valuable resources, then the cost of those resources will naturally rise to cover the expenses of those employed in those industries.
Sure, although I think there's room for reasonable people to disagree where to draw the line for various services. But taxi service? Seems way way out there in terms of costs and of minimal benefit.
State governments already operate special rural transportation services, like busses or even volunteers. Think people who are sick/injured and can't get to healthcare services because they can't drive.
It's not unreasonable to me that they would subsidize robo-taxis for those services since they are already funding services that are expensive or inadequate. Especially if there is some give and take to be had with regulatory overhead for the taxi service.
