It's kind of a only because of Telkom monolopy. The problem is, they own all of the ADSL infrastructure in the country, which is a huge deal. Other companies like DFA (Dark Fibre Africa) and Neotel have been laying their own fibre infrastructure, but it's pretty much dwarfed by Telkom's huge last mile network. It will take years, and billions of Rands for any company to come close to what Telkom owns in terms of national telecoms infrastructure. Also, we don't have any true Tier 1 ISPs in our country.
The other problem I think is, we have so much bandwidth available now with the Seacom and other cables being built, but we don't have the infrastructure to support big capacity. Maybe Telkom have some debts to pay off and they charging all their consumers more than what they're supposed to be. They actually are come to think of it.
They didn't want to support Local Loop Unbundling either, and will continue to charge consumers for a telephone line AND a data line, although both of them are unrelated. So for instance, you pay for a telephone line, even if you never use it. That's just the type of crappy company Telkom is. I think it kinda comes down to some more gracy train riding as well in the end.
I must say, the other ISPs in this country have made big changes to what it used to be like, with forcing Telkom to become part of the mutual interconnect rates. They're also forcing better service delivery from Telkom by delivering service much better than Telkom is at the moment. Anyway, Telkom should really start pulling a bit of finger and developing SA broadband, rather than holding us back and delivering a shitty service.