From David Poland, editor of Movie City News.com, Los Angeles, CA:
Studios went to a 55% flat rate of ticket share almost 10 years ago. That's one of the reason why films don't play as long. There is no incentive to hold them over. With something like "My Big Fat Greek Wedding," as the film kept running, the theaters got larger and larger percentages,
So if a new movie was looking for a screening at 90/80/70/60 in the first 4 weekends and could draw 4000 people over those 4 weekends, it might generate less than $8250 for the theater, aside from concessions.
(Math - 2000 in wk 1, 20k gross, 2k to theater... 1000 in wk 2, 10k gross, 2K to theater, 750 in wk 3, 7500 gross, 2250 to theater, 500 in wk 4, 5000 gross, 2000 to theater = $8250 to theater.)
"Greek Wedding" may be drawing only 2000 people over those weeks in its third month of playing, but at 50/50, the theater could earn, say, $10,000. Even with concessions, there was motivation to go with the older, less popular movie. There were even cases, it is said, when "Greek Wedding" paid only 40% in rentals to the distributor.
The other consideration is that with multiplexes in the 90s, there would be larger and much smaller houses, so an AMC could accommodate "Greek Wedding" in a 200 seat house and the big new movie in the 450 seat house.
As the studios frontloaded the theatrical, looking for the giant opening weekends instead of long runs, the financial benefit moved so much to the studios, whose films were running for fewer and fewer weeks, that exhibitors rebelled against 90/10 and down. The number for studio movies was averaging about 55/45, so they junked 90/10 and reducing and went to the flat, with a flat rate for house nut.
So now, when a movie is still doing well in week 5, it still loses theaters -- unless it's going VERY well -- because every weekend, new movies will come in with massive ad campaigns behind them and the multis can accordion out for the first weekend, putting films on 2 or 3 screens or as many as 10 or 12... and take advantage of the marketing that first weekend, then cut back to 1 or 2 or 3 screens on the second weekends. But there is still no room for long-legged film, because they don't pay more and they don't draw in those opening weekend pumped up numbers.
Hope this makes sense.