Car sharing is great. Sometimes you need to go somewhere for a couple hours and hiring a driver becomes very expensive. Or you need to transport something.
And I hate to break it to you but whatever you are imagining happened in these shared cars, the city bus has seen worse. Far worse. And you still get on those so, maybe not a big deal at all.
Idk where you live but all buses I have seen have no expectation of privacy, a bunch of people sitting inside, a driver and usually cameras. If you do... things... you must be insane and also cops meet you at the next stop.
If you live in suburban wasteland with crappy transportation then sure you need a car and I am sorry if you have to share one. But here in the city carsh is pointless. Taxi/bus/rail is for people who can do something better with their time than operate machinery.
It is interesting to me that you think that stops some people, or that an overly adventurous encounter is the worst thing to happen to a seat.
You may also genuinely be near a nicer and better maintained metro. Car sharing tends to be be much cleaner than the buses I've been on and biking about the same speed.
Also, here in the city, what bus is going to take you to your door the one time a year you need to move a piece of furniture? I've got some electronics to recycle - you're going to suggest the bus?
Oh but maybe thats the piece you are missing; car sharing is great because I can use a car the few times a year I need one without a hassle. Its not for just getting around, got feet for that.
In the city public transport gets me within 2-3 minutes of walking to the destination... if you need to minimize "walking" at all costs sure you'd hate transport but if I don't see why you would do that, unless you are disabled
And I hate to break it to you but whatever you are imagining happened in these shared cars, the city bus has seen worse. Far worse. And you still get on those so, maybe not a big deal at all.