The problem is the telco data rate is too high. In Vietnam, we have $3 for unlimited access to 3G data/month (ofcourse the speed is slow). Why didn't some Telco companies jump into the Angolan market?
Mostly because most Telco companies are monopolies that are not run by 3rd world people, and even if they are they still feel the right to milk it for every dollar; eg. Carlos Slim. I think though if China was to get into the game, they might drop the price like it's hot, but it's China.
"The key market strategy of the Chinese companies seems to be their competitive pricing, tailor-made for cash-stricken African countries."
"Huawei’s former head of operations in West Africa, Wilson Yang, quoted in a case study on the company by the University of Pennsylvania Wharton School in 2009, says that Huawei manages to achieve tremendous margins while still pricing itself only 5 to 15 per cent lower than its major international competitors, Ericsson and Nokia. ZTE prices 30 to 40 per cent below European competitors."