I think the last time I saw a "Auto Kino - car cinema" as we called them, must have been in the early 80s. And even then it was kind of a compromise. Yes, the screen was larger, you could smoke a joint or make out with a girl, but it had some serious downsides, too. Like in winter, or if was raining. The sound from the little speaker wasn't the best. And during the summer you had to wait till late evening before it got dark.
You are right, the video finally killed it , same as many normal cinemas as well.