That table stops at 2016 with driver comp at 43%, and the share was still growing at 3%/yr, and 43% savings is already a lot, so I'm not sure why you're writing

That table stops at 2016 with driver comp at 43%, and the share was still growing at 3%/yr, and 43% savings is already a lot, so I'm not sure why you're writing labor savings off. There's also efficiency gains to be had since computers don't need sleep, could have reduced insurance premiums, etc. I also expect that with lighter vehicles, the cost of labor is an even higher percentage of total costs.