You need to remember that things like streaming video and music are much bigger there than here - so those connection speeds are quite useful. I mean, even on a 4mbps line, a HD vid takes a while to buffer. I'm sure there are plenty of other applications worth considering as well that don't include any illegal purposes.
We just don't consider it because we've never really had exposure to these technologies.
Streaming on 4mbps takes long here because of shaping with our ISPs and contention/shaping along the routes from servers such as Youtube, Megavideo, Myspace Videos and the like. The actual bitrate of a 720p stream from a site such as Youtube is usually closer to 1.4mbps or so, you can thank the aforementioned for making those videos stream slowly.
Something to keep in mind is, 'what is being streamed'?
Look at what the vast majority of consumers on 4mbps connections use their connection for right now, when not looking at rich users that just want the best and the fastest; you'll often find that it's primarily for downloading anime (technically illegal or entirely illegal title dependent), downloading anime soundtracks (illegal), reading online manga (technically illegal or entirely illegal title dependent), downloading movies, downloading games, whether free or pirated etc.
You can stream internet radio using 30kbps AAC for a lot of stations, which amounts to pretty high quality in stereo; such a stream, run 12 hours a day every day of the month amounts to 4.75gb/month. In terms of cap, that'll be a non issue entirely for those running 384kbps/512kbps and an uncapped account. In terms of bandwidth, it doesn't really make a noticeable impact on even the 384kbps connection, coming in at using less than a tenth of its capacity.
You still can't stream videos (specifically 720p or 1080p depending on ISP, source and congestion along the route) properly irrespective of whether you have a 4mbps connection or even 8mbps due to the aforementioned; you can only buffer some of it and hope that while it's playing, there will be spikes of high-speed loading of the stream that'll keep you from reaching the buffer limit.
I can think of a variety of things that I would like to be able to do with my connection that don't constitute illegal usage that would still use up a fair chunk of bandwidth, however, a large portion of consumers wouldn't be doing the same things and would likely still be quite comfortable for everyday use (once you cut out illegal things they might have otherwise done) using a cap as limited as 30gb; the reality of this country is that people cannot afford a lot of things they'd like to have, so what they can get for cheaper or free, whether legal or not, they will. This is most often games, movies, music and other media that can be pirated, such as anime or manga.
Fansubs, I'm sure you're aware, are only sort-of legal until they get licensed by a company like Funimation or an equally lame american company that will ultimately butcher the series and throw on subtitles that make no sense. Once those titles are licensed, again as I'm sure you're aware, it becomes illegal to be in possession of or attempt to obtain the media in question, fansub or licensed version, in any format that is not the purchased DVD or an otherwise online-purchased DRM protected (think windows media guide online store) version of the media.
What do South Africans do? LANs, internet-based downloads. We can't afford or don't want to have to suffer the horrible subbing and dubbing of the Funimation etc releases, so we don't buy the DVD or online versions and obtain the fansub versions instead.
End of the day, illegal activity. :/
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