Also read between the lines in that article .. they're not planning on competing with other broadband offerings but rather trying to pitch yet another overpriced "premium" product to a different *small* market segment (those who need portability). In other words rather than a mainstream product with mainstream competitive pricing (i.e. utilise economies of scale to offer a low price to many people, like broadband is in other countries), they're going to keep the price high and sell it to a small number of mainly business users and hobbyists who are specifically interested in the portability aspect. This neatly prevents them from having to lower their ADSL prices in response to a cheap wireless offering as well as prevents them from having to spend any money upgrading their local bandwidth infrastructure to accomodate hundreds of thousands of broadband users as should be the case (even though they have the money to do it .. disgusting).
Telkom will not compete with itself, i.e. they don't want the WiMAX division to compete with the ADSL division (even though they will give the impression that the two compete in the media by touting the benefits of each) .. so they pitch each product at a different market. Expect to see ADSL prices remain similar, and for WiMAX prices to come in in a similar price range to ADSL, and with Telkom making a lot of noise about "business users who want portability" rather than Joe Public.
The only hope is if a company like iBurst decide to compete in the mainstream market. Sentech is out - we already know they're using the "premium pricing for small market size" model, Vodacom won't do it because Telkom owns 'em, MTN do whatever Vodacom does anyway ... so the only company that might still decide to go for "economies of scale" (i.e. low price e.g. R350/mo and hundreds of thousands of users) is WBS with iBurst. Let's hold thumbs, because that is what SA needs - not YET ANOTHER overpriced "premium" product aimed at the wealthiest 0.05% of the country, but a price at which at least 20 or 30% of employed people could afford (for comparison ADSL has around 10,000 users and Sentech probably between 2000 and 3000, off a population of 40,000,000 and a "first economy" population of probably at least 5,000,000 - so these numbers are WAY too low - compare to e.g. in the US where over 50% of the population (150,000,000 people) now have access to broadband at home). If just one company does it here, and succeeds, it could trigger some *true* competition and price wars here. Economies of scale can be effective in broadband because then you get all those users who use very little bandwidth subsidising the high-bandwidth users, but you do need to invest in big infrastructure - the problem here is they aim only at the early adopters who are usually the high-bandwidth users, and their prices are so high they pat themselves on the back for only getting the early adopters.
In developed countries broadband is a horizontal market. In SA they turn it into a vertical market, because it's easier to skim a lot of money off a few of the wealthiest people if there is no competition.