I don't know what the story is behind this but if Apple is upgrading people I'd say it's a smart move. Call it the "Gmail Rule" which states "You should give people a monstrous amount of storage because it's great PR and 99.9% of people won't come anywhere near using it anyway"
End Result: Happier customers for almost no cost (With storage as cheap as it is the .1% who do use a lot of space will still be relatively cheap to maintain)
There is a difference between email space and storing files. It is hard work to store lots of emails. Particularly when gmail has a limit on size of attachments. Data storage, easy to abuse.
You're certainly right but I still think the number of power users who would even be able to fill 1TB worth of space is minimal. I mean, your average Mac is only sporting about half that. Plus, since you can't exactly stream your audio/video files of iDisk I'd imagine that would cut down on a lot of abuse (since most people want their media on hand)
It's a lot of work to store this much data too. 2TB would take weeks/months to fill up on almost everyone's internet connection (5 megabits up = 39 days).
I'm sure it's a fluke but it does raise a point: Apple is missing an opportunity to make MobileMe a really strong companion to Macs & iPods. They could build it into a comprehensive online backup/syncing tool. Buy a new Mac or iPhone, plug it in, download your data in the background (stream on demand, tie into Bonjour for first backup if both machines are on the same local network) Considering storage is cheap it seems like a no lose scenario for Apple. Some companies are getting by offering huge amounts of cloud storage for far less than the cost of MobileMe is today.
End Result: Happier customers for almost no cost (With storage as cheap as it is the .1% who do use a lot of space will still be relatively cheap to maintain)