Not sure I’d agree on the pace of development. This has been in development for over 20 years. Check out this write-up and links of the 1995 “hands off” journey of a Carnegie-Mellon project car.
https://www.csd.cs.cmu.edu/news/then-and-now-2850-mile-no-hands-road-trip
This was part of a project to automate portions of the highway so that cars could “platoon” in close formation to increase traffic density. Here is a video from 1997 about the PATH project.