Can't see what the issue is
Frankly, disk space is so cheap it's ridiculous. Today, anyone with a PC at home can easily get over 300GB of disk space. Aside from rabid gamers and filesharers, that is largely enough for reading mail and the occasional surfing.
And for companies, with incomparably larger IT budgets, I really cannot imagine they'll be interested by an online storage space - what with the security issues, the payment arrangements (you'll probably be paying by the megabyte both written and read), and the lag (you don't get 100mbps lines yet, do you ?), I just cannot imagine the users will be happy.
Why is Vista not selling ? I think the essential issue is the perceived performance. Taking 15 minutes to delete a file is simply unacceptable. In the same way, a remote storage area accessible via Internet is not going to work better either, because of the same performance issues. I don't care how much money you're ready to throw at this, there is simply not enough bandwidth available to get gigabyte speeds to thousands of companies.
And I cannot imagine users being content when they have to wait 10 minutes, or even 5, for their very important rush-job report to just open, let alone get working on it. Autosave is going to be a nightmare. And what about unexpected connexion issues ? What about ISP issues ?
I'm sure there are companies with solid IT practices that never experience any downtime. I'm also quite sure that a backhoe can cause a lot of trouble in very little time. You don't often find a backhoe on company premises, now do you ?
For all these reasons and more, I just fail to see how online remote storage is actually going to do any better than remote HelpDesk call centers.
But hey, that doesn't mean that some Fortune 500 companies won't buy into it, as usual.