Many of us thought we'd be riding around in AI-driven cars by now -- so what happened?

Car manufacturers know: There's a huge amount of interest in AI-driven cars. Many people would love to automate the task of driving, because they find it tedious or at times impossible. A competent AI driver would have lightning-fast reflexes, would never weave or drift in its lane, and would never drive aggressively. An AI driver would never get tired and could take the wheel for endless hours while we humans nap or party. While AI does need huge volumes of data to program and guide it, that shouldn't be a problem.