What you're suggesting in the first paragraph is price fixing, and because there are multiple companies it would require collusion to pull off. Not saying it doesn't happen, but generally speaking in capitalism competition will push prices down. That's why buying a TV is so cheap, and why you can get bananas for almost nothing still. Most products prices are pushed down by competition from multiple companies.

The robo-taxis themselves probably cost on the order of $100,000 at the moment, due to all the extra computers and sensors and stuff on top of a standard EV. Spread out over their expected lifetime of say 5 years at 20 hours per day, that's only $2.70 per hour.

They're electric, so there's that cost too, lets say they drive their maximum charge per day (400km) which is actually quite high for a taxi, that adds about $20 per day in electricity costs, or another $1 per hour.

Maintenance on electric cars is almost non-existent, you pretty much just need to rotate and replace the tires and change the cabin filter. This isn't insignificant, you'd change the tires every 100 days or so with that much driving, but you're talking about $5 per day, or $0.25 per hour. That's literally my entire warranty work for my EV. There simply aren't as many parts to wear or break as in a gas vehicle.

There will of course be other costs like regular cleaning, and fixing the upholstery from wear by patrons, I can't estimate that, but I suspect it's not a huge amount. Plus insurance, also cheap per hour when you're operating that much.

So the total operating cost for a robotaxi per hour is around $4-5.

Even the cheapest taxi driver is going to be making what $15-20 per hour (with tips), in some cities it's double that.

So the cost to the company for running is going to be 75-80% less with a robotaxi fleet.

The price per hour for robotaxi's will also continue dropping, as EV battery costs come down and the self-driving technology matures they will be able to produce these at scale and go from a $100,000 current price to probably $50,000 over the next decade. The price of labour is going to keep going up though.

These big companies investing in self-driving systems are spending billions because they know how much money will be made on them. My wife and I pay about $300/month to have a second vehicle that we use only 5-6 times in that period. If I could have access to a $10 per trip robotaxi it would make far more sense to drop that second vehicle and use those services for the odd times I need it.