The Chinese are starting to feel the squeeze of their growth in many industrial activities as they struggle to find enough qualified workers. So I don't know if you need to be that worried about SA's 'core industries'.

The thing with clothing is, you don't need your workers to be qualified for the labour-intensive steps in the production process (= the final assembly). I've seen estimates that there are more than a hundred million low-skill Chinese left to be integrated into the labour market. This means that China can continue to compete on labour costs in clothing with the poorest developing countries for another decade or more.