It depends so much on where you live, your work, lifestyle, etc., etc.
I survived in a city with decent public transit until age 30 without a car... then got one and got lazy. 🙂 I still own one. Being self-employed, I'm not out everyday on a job, etc., so don't fully utilize it, but the convenience is difficult to beat for situations that change at short notice. Last year the engine was replaced (it's a 2004), which took a few weeks to find all the pieces, get it back together and squash all the new bugs that arose. During that time i rented when needed. It got me thinking about joining a car-share service. Almost did it. Those seem great if you need a car for an hour or two, but for longer periods, renting seems the better option. Looking at my annual car ownership costs (maintenance, depreciation, insurance) and my relatively infrequent driving, I could probably rent and either save some money or break even. But there's no denying the convenience of having the car in the driveway, ready at any time.
We'll see what happens with autonomous vehicles and the predictions of some that it will become a situation of low individual car ownership and massive scale on-demand car sharing/renting. I wouldn't mind this if a high positive customer experience level was maintained.