[rdl]

Guaranteed demand, parking (there are legal issues where being an individual or first party business owner of vehicles is easier than being a ZipCar). You're leasing cars for ~$500/mo for 36mo each. That gets paid regardless of demand. If your stable gets used enough to bring in >$500/mo in external customer net revenue per car, that would be pretty exceptional. Most likely you'd make $100/car/mo and get a bit of extra professional maintenance for the fleet vs. just owning them and having a dealer service.

What's interesting is if car manufacturers start to develop vehicles specifically for this kind of market. I'd love to have personalization settings (nav, seat, climate, driving controls, etc.) which follow me as a driver across a fleet of identical or related vehicles. You might also have a "valet mode" (some cars do now), "renter mode", and "owner mode", with different performance limits (I can ruin a $1-2k set of tires in 10k miles of spirited driving, but if I ran the right profile on the car, I could make them last 30k miles). Might also make some maintenance/safety things non-overrideable for renters -- you can't start the vehicle if the brakes/tires/fluids/etc. are not good, for insurance and vehicle-damage reasons.