iBurst is wireless after all, it is incredibly limited resource. Why iBurst is outperformed/more popular than ADSL:
1) Gamers. High latency. ADSL can get sub 20ms (with nearly no jitter -- both local and international), while iBurst is above 40ms (with jitter about 10ms local and 50ms-100ms on international). Gamers won't touch wireless. It's technological limit!
2) Reliability. Speed is same mostly, without dropping in middle and constant speeds. I cannot stream videos for that reason, even bitrate is smaller than It's technological limit over distance "coverage dependant". Much worse that line attenuation (I have very unstable dial-up speeds), currently, it is same distance from exchange and tower, yet I could have 512k instead of dial-up.
3) Downloaders. Can work on any protocols without limits, no "current IP downloading already" junk from rapidshare-like services and no limit on streams with P2P. It's technological limit or rather provider limit, other wireless providers don't do that, even if they are uncapped.
Even is iBurst was uncapped, I would not touch it -- I cannot use it to full. Unless for browsing, wireless has no future. Fixed line is the future.