By international standards there are very few great wines produced in South Africa. In fact considering the amount of wine actually made in SA it is strange that so few are world class. In volume produced it is 7th in the world which indicates that yields are much higher than in other countries. In fact average yields in SA average around 15 tons per hectare which would be unheard of in some French appellation controllee wines. The other factor is pure economics.
Land is relatively cheap and so is labour.
By irrigation yields can be pumped up and so the temptation is to go for volume, especially if you sell your grapes to the co-op at a fixed price per ton regardless of quality. Actually not a bad strategy if the guaranteed price holds firm. But even an 'O' level economics student can see that this cannot go on for long. It is almost as crazy as the Common Agriculture Policy in Europe that has destroyed the quality of farm produce, precipitated huge gluts and strange diseases in livestock, paid the big farmers huge sums to set land aside and will in the end put most small farmers out of business. Very few producers are fortunate enough to be totally uncompromising.