SAA is expanding their African Route Network so they're freeing up Aircraft from less profitable routes. Im not saying DUR-CPT was not profitable im assuming they can make more cash in Africa than they can in SA's very competitive,over capitalised domestic market.
I was on a Mango Flight recently and according to their inflight magazine , they will have wireless internet available in the near future. Its not all doom and gloom for the businessman. I know it doesnt make up for legroom but at least its a service you wont find on SAA.