I've thought some about what it would take to set up a system for failed startups so that customers could be assured that their data / services don't disappear when a company goes bust -- something similar to the Free Qt Foundation that KDE has setup with Trolltech:
Here at salesforce.com (the company that does cloud computing/saas for businesses,) we have the data loader tool that customers can use to download all of their data locally as often as they wish. Also, there is an API so people can write their own backup/restore/integration code.
http://www.kde.org/whatiskde/kdefreeqtfoundation.php
I think that's a difficult problem for software-as-a-service to overcome.