I'm not sure I buy that scenario...
Is there any other market where random consumers are basically acting as financiers for a commercial fleet of equipment? What's the reason for the fleet operator to involve those customer-owners at all?
In terms of immediate cost, it will be cheaper as a customer just to use the ride sharing service yourself, since you won't have to pay car payments you'll just pay the rideshare fee. Especially if the self driving software gets priced in the $10,000+ range as Tesla has suggested it will end up.
So anyone in the "budget" category will just be buying rides not vehicles. They'll have to wait 5 minutes for a vehicle, and they won't get to have their vehicle of choice, but they also won't have to deal with the hassle of running a mini carshare business, whatever that will entail.
Most people in the "premium" category isn't going to want random drunk people fingerblasting each other in the back seat of their nice car, so that cuts out the top of the market.
That leaves what... people who want to save some money but also really want to own their own car, but also are comfortable sharing it with random people?
Seems like a weird segment. Why wouldn't the fleet operator just buy cars and own them? They're going to be burning through these vehicles every 5 years anyway, what's the point of parking them in a random owner-operator's garage and having them taking it out of the fleet when they feel like it?