DH bought a used Scion tC for DSS. He found it before DSS was old enough to drive it, but it was a good deal and he bought it. DSS drove it all the way through college and even later. He bought a new Camry in early 2019, which would have had him driving the other car for like 10 years, maybe?
Most of my friends with multiple kids either gave their kids old family vehicles or bought each kid a used or new car.
My parents weren’t rich by any means, but I did get a new car for my 16th birthday. I drove it for ten years, and when I got tenure I bought myself a new car. My mom took my old one and drove it for another 11 years, then sold it to someone who drove it for another 5 years. Definitely got their money’s worth with it.
DSS and I were both only children, which I’m sure makes a difference. I know one family with five kids, and they send their kids off to college with a car, but they don’t have one before then.