Agreed, I don't believe there will be any such autonomous coordinated cars in many decades. It is a seriously difficult problem for the general case. It's effectively AI and true AI has been just around the corner for many decades but never arrives.

For the happy path of interstates in good weather, sure, that's not too hard.

I think the closer we get to the point where all vehicles are autonomous, the easier it will get. The interim is the hard part. Right now autonomous vehicles have to be able to operate alongside human operators whose ability to communicate their intent is limited to brake lights and turn signals, and there is basically no way to cooperate. Now imagine a world where it's all autonomous vehicles who are constantly communicating intent and can cooperate in marvelous ways, like with orderly zipper merging or intersection management without the need for traffic signals. There will still be a need for computer vision to detect pedestrians, obstacles, and wildlife, but it will be simpler than having to deal with other human operators.