Ironically, it might be the walled-garden ecosystem of tablets that ultimately leads to mass end-user adoption of Linux. The desktop introduces too many complications -- there is a much larger set of use cases, and thus a larger set of situations where a Windows-convert can get confused, discouraged, or frustrated. Tablets, on the other hand, with their relatively fewer ubiquitous uses, can be fine-tuned in way that requires little-to-no end-user servicing. If Canonical can employ the Apple/Android software store model with enough flexibility that power users can still make meaningful modifications, then this could be the biggest thing to happen for end-user Linux in a long time.