Yep, the last one closed here in the early 80s.............my heart was broken when I heard the news.
Most of the rest will be gone soon.
The studios have almost completely switched to digital format. The projectors are big bucks, and most of the drive-ins still operating don’t have that kind of money.
I lived in Loma Linda, California, in the early 80s. Me and my buddies used to sit on the back wall of the Tri-City Drive In and watch movies for free. I left the area in 85, but I’m sure it must be closed by now.