In 5 years, the Andriod OS will be fading away and Windows and iOS will be the predominant ones. Main reason: Android doesn't have a desktop interface to work/sync with well.
Hmm. I think desktop interfaces are getting less and less relevant now. If your contacts, calendars and email get synced to a web service, you could then sync them to your desktop. On Macs it's easy to set Google to provide all these, not sure how well it works with PC's.