Why wouldn't they be able to get 20 trips a day? Seems like 10 is low balling even worse than the 250 was for a car that can be available 24 hours minus however

Why wouldn't they be able to get 20 trips a day? Seems like 10 is low balling even worse than the 250 was for a car that can be available 24 hours minus however long maintenance and cleaning takes.