Raising three kids with one car. Made easy because I bike to work, but one of us would leave the other regularly for errands without issue, but we could walk, bike, and take mediocre transit if needed, which we just planned around. Not even inconvenient 90%+ of the time and another 9% took a small amount of coordination. The other 1% of time (or a few times a year) we delayed a trip, called an Uber, or asked someone else for a ride. That few times a year was never worth buying a car for.
Note that car seats in and out of taxis/Ubers and hauling them around at your destination can be a huge pain, especially for larger seats and if you have more than one. But they have to let you do it and that should only be rare circumstances. Our kids loved taking the bus and it was much easier for trips it worked. Plus walking/biking/transit/navigation like Fru-Gal mentioned are all essential life skills.
Furthermore, my thinking has matured from one-car(well, van)-no-matter-what to hmm-maybe-adding-an-older-hybrid-would-reduce-our-total-costs. The key is to not make driving a daily necessity and then habit so that a second car doesn't mean twice as much driving. EDIT: and all the vehicles should be old/cheap so depreciation, insurance, and tax are low.