I rarely use my car, I'm the exact kind of person this is aimed at. I haven't used it in *monthts. But when I need it, it's there. There's car rental place about 500 meters walking distance from my home, but they aren't open 24/7. There is also a ride share car parked at about 1km from my home, but it's only one car and if someone else took it I can't use it.
These things only work when you know well in advance you're going to use it and even then, they might not be available at peak times. There's only so many ride share cars available, and if everyone wants to visit their parents on Christmas, there's not enough of them. Car rental companies aren't going to buy enough cars to cover their 5% peak use either.