If Linux will continue to draw regular PC users away from Windows, it'll need to have many of the same features as Windows. That includes for-pay network services that require Linux clients, such as remote backup.
Windows and Mac users have endless choices: the native file- and system-level backup and restore tools in both OSes are also complemented by a slew of commercial backup solutions. Services like Mozy and Carbonite perform silent, encrypted differential backups to a remote host, so a user's data is protected consistently and stored off site. But neither of those services offer Linux clients (at least, not yet).
A Linux user who wants to perform offsite backups generally has to resort to using a native Linux application (such as the Simple Backup Suite in Ubuntu) to back up to a remote server that isn't specifically for data protection. There's no shortage of Linux backup clients that can speak to a remote server, like the Simple Backup Suite that's available in Ubuntu, but again, integration with a commercial backup provider for regular users is what's missing.
One very likely possibility is that as things become that much less platform-centric, the idea of needing a platform-specific client to perform robust backups (not just data, but whole system states) may become as quaint as, say, only being able to access specific Web sites with specific types of Web browsers. The other, more likely possibility, is that full-state backup services dedicated to supporting Linux clients will step up.
Most of what's wrong with Linux isn't fatal: if it was, Linux would scarcely have achieved the degree of adoption it now enjoys (with the general exception of consumer computing). But there's little question these problems need to be fixed, and that doing so may require some challenges to the conventional Linux way of doing things and defending the results.