Dear DUmmies,
The reason the drive-in theater is no more is because it was highly uneconomical, considering the cost of land in even suburban areas for one, and double for the fact the quality basically sucked compared to more modern theaters.
It's also one of the bigger reasons I almost never go to regular theaters either--for the cost of a Netflix subscription, a DVD, or Redbox rental, I can see something at MY convenience, without some asshole's cell phone, crying baby, or chatterbox idiots, and not pay $30 for a couple of cokes and a bucket of corn, on top of the $12/ticket ($15 if it's one of those IMAX or 3D flicks.)