You would never buy a car without cup holders like you'd never buy a car without seat belts. A secure place to store your scalding coffee so you can concentrate on driving and put both hands on the wheel isn't a convenience—it's a safety feature. And it wasn't even standard on cars until the 1980's.
Bon Appetit has a wonderful deep dive into the history of the cup holder dating back to the original patent from 1953. Automakers tried many different implementations of the concept, but the tech didn't stick until the first Dodge Caravan hit the market in 1983. It took thirty years for some of the biggest corporations in the world to sort something that fundamental out. Sometimes even the most obvious technology can take forever. [Bon Appetit via Consumerist]