If you want to be a drive-in owner, then I would definitely encourage you to go for it. Many of the original drive-ins are gone, but many of the ones that have survived are doing reasonably well. A few are being reopened (or being built from scratch) each year, so we gain a few as we lose a few.
On the other hand, if, as it appears, your main motivation is to discount, then I'd caution you to think that over. A drive-in may be a little less expensive to operate than an indoor, but not necessarily by a lot. You trade the cost of indoor square footage, heating and air conditioning for a lot of outdoor maintenance. You also have a shorter business day than an indoor, so your income-producing potential is much different. In some cases, you might even be seasonal, requiring you to think like a farmer, who makes all his money when the crops come in.
Cut the price 50 cents or a buck if you must, but consider that many people will attend a drive-in for the kind of experience that no indoor can offer. There is value in offering an experience where people can load their families into the car or pickup, sit in front of an 80-foot screen under the stars with a bunch of others and watch TWO films, usually for less than it would cost them to watch a single movie at an indoor. Concessions are usually more reasonably priced as well. For what you have to do to provide that experience, you really do earn your money.
There's also the relationship with the studios. If you intend to use a discount model to attract customers, you're not likely to get new films. After all, the studios make their money from what you charge at the boxoffice, so if you're giving it away (or nearly), why should they get excited about working with you?
Finally, there's this small matter called "digital cinema". You're looking at a much more significant cost to get into this business now, because the reliable old sewing machines you once could find used (and relatively cheap) are nearly obsolete. We drive-in owners are faced with the same concerns everyone else is regarding the cost of conversion. For seasonal operations, this is an even more challenging issue. Building a new booth won't reduce that cost much, if at all. Everyone knows the money to pay for it all has to come from the customer, somehow.... oh, and were you hoping to draw a reasonable salary for yourself, too?
I would really give this some hard thought. You've got a great idea, but the "cheap night out at the drive-in" is really a stereotype that's becoming harder to sustain. Even at a slightly reduced price, no other theatre can duplicate the experience. Don't get caught up in the idea you have to sell it cheap and you'll likely be surprised how well you'll do.
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