I think the strongest argument against this point of view is that the drivers can opt to work for multiple car services to get a handle on their price structures. It's certainly possible for a traditional employer to allow that arrangement, but you have to admit it is an uncommon thing.
It's much more analogous to a contractor working for a general contractor -- if I'm a plumber I can take gigs from multiple general contractors, and my ability to negotiate with the customer directly is very limited; instead I'm usually left negotiating with the general contractor, often just with a take it or leave it price. The general contractor is not the employer in this case.
It's much more analogous to a contractor working for a general contractor -- if I'm a plumber I can take gigs from multiple general contractors, and my ability to negotiate with the customer directly is very limited; instead I'm usually left negotiating with the general contractor, often just with a take it or leave it price. The general contractor is not the employer in this case.