No one will ever pay $25 for a movie when stealing it is so much easier. Even if DVD and disc and owning it goes up to $40 a movie, no one will spend insane amounts to see a movie, it's just stupid.
But they really need to rein in the spending. You want to know where the money goes? Towards hiring hundreds of crew members to sit around for two weeks as you close downtown Rochester NY to film two damn scenes. I watched for hours and they never filmed anything.
Also in 1982 very few people had VSRs to play movies on, so yeah movies stayed in theaters longer.