The last two carriers to do this, although unwillingly, were Swiss Air (Swiss) and Sabena (Brussels SN). I don't think that it is a good path.
However ... I have long subscribed to the view that we are going to have a few mega carriers, just as soon as countries allow themselves to give up the idea of a 'flag carrying airline'. We no longer have one in the UK, as the former national airline is now a publically owned company - albeit the rules still state 51% majority UK owned. But that is paper only.
When the costs finally get too much (people like KLM/AF are high up the list to learn the hard way) then the new mega carriers will be formed around the existing alliances: One World, Star Alliance, Sky Team and so on. Since Africa has clearly demonstrated that it does not want/cannot provide (you choose) an integrated and harmonius network of hubs for the continent, SAA need to ensure that they are well inside any of the large alliances before it is too late.
That said, I reckon SAA have another couple of years to go before they are in real trouble. The desire of the new owners (Mbeki and Co) to show that they can run an airline (oh yes, and a country) are strong enough to keep SAA alive. For the time being.