There's an old drive-in less than 3 miles away from here, it's been closed for more than 25 years. The framework & shell for the screen seem still good, though the screen probably needs to be replaced. The parking places are all grown up with pines, trees getting pretty big now, could be sold off for pulpwood. Projection house/concession stand would need complete re-do,maybe raze & rebuild. The one place they could save would be on speakers & poles, no longer needed! A small AM or FM transmitter would take care of sound. But our area is low in population & economically depressed, & it would take *years* to recoup the investment- if they ever got it back at all. The owners have shown no interest at all in trying to revive it, & sad to say that they're probably wise in that decision.
Central air conditioning, VCR's & cable TV all became common by the early to mid 1980's, & drive-ins became unprofitable. Too bad.