Can I suggest a possibility, as Akerosid has mentioned earlier, arriving in Europe at 9pm doesn't give good opportunities for transfer and onward travel, but consider also the takeoff time, it would be at Noon, at 5,500 feet ++ and in Summer at 30 degrees ++, could limit load factors.
It has always been this way, certainly since the '60's when the Sultan first flew that route, when there was always an intermediate stop, Kinshasa for Swissair, Nairobi for BOAC, and Sal for SAA, oh the good old days of apartheid, when nobody wanted to know South Africa, but gold is gold....