As Waymo's driverless cars spread, the reactions are piling up from every direction. In San Francisco, Amazon's Zoox is angling to challenge Waymo for market share; Lyft is musing about a future where its human drivers service Waymo's fleet instead of competing with it; and in Minneapolis, city officials are weighing a rule that would force Waymo to keep a human behind the wheel, citing fears for rideshare jobs.