No it is a good question. Does private solar aid the lower class? Well "lower class" in South Africa means real poverty. So they certainly can't get solar themselves. As to whether higher income households going off-grid helps - its tricky I think.

On the one hand, private solar does lessen the burden on the grid. We currently have had a good few weeks without load shedding, one major contributing factor of which (acknowledged by Eskom themselves) has been a combination of good weather and off-grid solar households. But on the other hand, Eskom is increasingly deprived of the rates to pay for the large capital investments needed to upgrade the grid. Eskom has continually hiked those rates (which means more people are incentivized to go solar - it is a vicious cycle perhaps).

Our government is finally moving forward with a policy of allowing private enterprise to contribute to the grid. I think this will definitely help. But realistically, I think South Africa will have to deal with load shedding for a good few years.