Not everyone downloads 100+GB of torrents! My typical usage:
30% Streaming (when I'm awake)
20 % General Browsing/updates (I think this is when I'm awake as well)
30% Gaming (stretching it to just before fall asleep, but still I'm awake)
20% Torrents (see below)
Now on my +-80GB of usage this = about 16GB for torrents (let's say it is movies). 1.5GB per HD movie = about 10 movies. Now our typical scenario is this. It is 7pm and we feel like watching a movie. Well since I have a nice 10Mbps per line, I browse what is new and we fancy watching, kick off the download and by 8pm we can watch it.
So this can happen about 10 nights out of the month some weekends we may watch two on a Sunday.
The point is I use the internet when I'm awake because I don't want to start a pirate movie shop in my spare time

and by the looks of it there are other people that feel the same. Now take an ISP like WA, they seem to cater for heavy downloaders (which is what uncapped should be for), not for the average guys like me. You might say but the "midnight data" is free or a bonus, but then that makes their standard capped packages very expensive and not competitive. Yes I do get what I pay for, but at the end of the day I decide who I want to pay and what is of value to me.