I don't know about
S.o.S. but, as we get older, we find the 'indirects' more tiring and pay for the direct routes.
Although I have found that, sometimes, the indirects are not that much cheaper. For South Africa, I have checked and used: Lufthansa and Turkish (never again!). Would use KLM if prices substantially lower. By the time you go over to Zurich, you are taking more time.
I did use the old Sabena a couple of times. The cabin service was very poor and you always had a bounce at FIH at Kinshasa. But they were running 747-300s on the route (1990s) and if you could get Biz upstairs it was very good. The txfer at BRU was superbly timed and organised. The one time we were delayed back from JNB they put me up for the night in the airport hotel. The delay was not their fault.