I used ZipCar when I lived in Chicago and Seattle. Great service. Didn't need to own car in either city because of ZipCar.
I've never used one of the Bird-type scooters, but I used to commute to the marina in SF on Scoot. It really was the most fantastic way I've never gotten to (and from) work.
This is just a car rental for a shorter amount of time. And in D.C. we had something called ZipCar which was pretty close to that.
It's like tourists in rental cars but worse, since these people often have never owned a car and drive very infrequently. I know people who never drove until their 30s then got a drivers license just to access zipcars. They're exceptionally bad drivers.
Personally I prefer these people use electric scooters than N-thousand-pound >100HP vehicles.
Alas, as a cooperative it's not profit oriented and there are certain restrictions, notably that vehicles are location bound and need to be picked up and returned at fixed stations.
That said, with a bit of planning it releases you from the dirty details of car ownership and this for much, much less money.
There are other ventures in the form as you describe it (private ownership loaned out). But to the best of my knowledge that never caught on.[2] (German and French only)
[1] https://en.wikipedia.org/wiki/Mobility_Carsharing [2] https://sharoo.com/
Just charge per minute and allow the owner to track the position continuously.