What is the practical difference between owning a vehicle, and having access to one whenever you need it?
It's like having a really, really big purse or backpack.
Additionally, if I spill something in my car, oh well, maybe I'll steam clean the upholstery after a few months of such spills, but if I spill something in a shared vehicle, that seems worse to me--letting the mess build up for a few months impinges on others.