They need large Chinese production lines for lidar, integration kits for cars plus the in car computing, repair pipelines for both sensors and cars, real estate to park cars, the infrastructure/processes to clean and charge them quickly, teams of remote drivers, insurance policies, etc. Then they need to compete with mature decentralized Uber and taxi fleets who push their car/maintenance costs onto drivers, while Waymo grows adoption of their mobile app where prices will matter if they aren't as perfectly reliable and low risk as hiring a human. The self driving novelty effect won't last forever

All of that requires large capital expenditure and careful business models