if you really have self-driving taxi and it is cheap, I don't think it is difficult to acquire customers, since customers are not loyal to taxi brands, they are loyal to price
It’s quite a delicate balance between supply (cars) and demand (riders). If you have too much supply, you aren’t making money because you have to subsidize all the cars without riders in them.
If you have too much demand and not enough supply, then wait times shoot up, and people return to your competitors.
Plus demand is non-uniformly distributed across time. If you have enough cars to handle peak demand, then they’ll be sitting idle the remainder of the day/week.
Most people think that trains are busy, because most people ride trains in high-demand times of year. If the same is true of a TNC, then it’s much better to list your cars with a bigger network and let them keep your cars busy more than you can.
It’s much more expensive to properly balance the marketplace than you think.