Urbanization has been continuing apace, and in urban environments ridesharing apps generally can have a car at your doorstep in minutes. Sometimes as little as 1 minute. Generally not more than 7.
When you factor in not needing to find parking, and no need to walk to and from your parking spot, it absolutely saves time.
Queuing theory forms a mathematical basis for analyzing the problem. So far its been heavily analyzed and applied towards dynamic pricing models. But if you want to replace cars people need to feel confident they are going to have a ride available in a short amount of time and not be price gouged.