Hep
Striker
just need to be lower than car ownership to make it viable.It would need to be ridiculously cheap for people to go for this.
Could be subscription-based or per use. It also allows you to use different classes of vehicles as you need them. Trip to the off-license - small town car. Moving a bed, a large van and so on.
As long as the car arrives within a couple of minutes, it's pretty much the same as car ownership anyway.