Daimler-Benz demonstrated autonomous driving with little human intervention over long distances in the mid 90s [1]. Other German car companies had similar programs. So they are certainly capable of doing it, not sure why they did not push it to the market. Too expensive? No demand? Too hard to tackle the last couple of percent of required human intervention?

[1] https://en.wikipedia.org/wiki/History_of_autonomous_cars#199...