Here's the problem, at R199 plus installation for 20GB I might as well stay on mobile. And that's the reasoning for most people. These providers including Vumatel still has a long way to go in learning how to make fibre worthwhile.
For R200 p/m one can get 5 GB of daytime data and 15 GB of night time from Cell C (I'm not sure what the other guys are offering). For that same price one can then get 20 GB anytime data on fibre (most people on mobile don't use their night time data very effectively). On top of that one then moves from wireless to a fixed line with consistent, reliable, and fast performance. I know of many people in my area that would like to do this because they are frustrated with wireless.
I think this is a great strategy, moving people over to your network, and for less than double one can then get ten times more data. How they make money from this I dont know. Vuma uses AON which is more expensive than GPON, and the GPON guys ask abour R300 per port. At least in this way they get R200 from that port where they potentially would have received nothing.
Unfortunately it has to be worthwhile for both the fibre provider and the customer for it to work in the long run. If it is only worthwhile for the one, the other will not come to the party, and then there will be no party