It seems hard to say for sure that costs will be lower. The cost of a fully-autonomous/self-driving car is still unknown. Even if google is currently at the 90%, it's well-known that the last 10% is always the hardest. That last bit is especially important when you consider the consequences of imperfection in this venue.
I meant that the incremental cost of paying a human driver would be gone. The fixed cost of inventing and developing the self-driving technology would be minimal because it is amortized across all self-driving cars.
