I'll bet outside counsel after their fatal Arizona crash looked over the tech, looked over the competition and said "you will never succeed at this, you will never make money at this, especially now that you've agreed to forego all the patents you stole from Google that were the overwhelming bulk of your strategy." Pulling out of trucks first allowed them to miss most of the headlines. I'll bet they skunk autonomous vehicles in their entirety soon; I took an Uber a couple weeks ago (because Lyfts simply weren't available) and holy shit has their app become touchy-feely. They're clearly doing everything they can to erase Travis Kalanick and day-late, dollar-short autonomy probably isn't a good fit with their current business model ("Uber: the smiling slave drivers!™").