You have it the wrong way around Deskjocky.
The route has been re-introduced based on requests from lodge operators in the area. Virtually all the lowveld bound pax travelling from CPT do so on Link. The price of Link's tickets on that route combined with connection hassles some lodges are experiencing via MQP are motivators for the re-introduction of the route.
I believe Link will experience a slight reduction in load factor on the CPT-MQP sector, rather than SAX on the JNB-HDS sector.