At which point, your costs = costs of owning a car for each commuting user in your area + overhead + profit. So unless you are offering subsidized prices, it will be cheaper for everyone to just own their own car for commuting.

Only if you assume everyone commutes to work at exactly the same time. Rush hour _is_ a thing, but even during rush hour you're no where near the point of having 100% of cars on the road at the same time.

You're also forgetting that most existing cars on the road have way more seating capacity than needed, since they need to account for the maximum number of people who will use that car at once. A family of four needs a car with four seats, even if most of the time that car will only be carrying one person to work and back throughout the week. Self driving cars will be much more efficient in that respect.

> Automatic Rideshare companies can self balance over a large area, watch the predictable trends that show up during a year [...]

That assumes that nearby places have different peak times, which is probably a flawed assumption.

Over a city they definitely do. Such as rush hours. Move the cars to the residential hours in the morning, move the cars to the schools & commercial areas in the afternoon & evenings.

You can also vary your pricing. Planes and trains charge more at peak times when services are in the most demand. Uber has "surge pricing" when there are unusual demand spikes.

By offering discounted fares at off-peak times, and charging premium fares at the busiest times, you can smooth out the peaks while optimising profitability.