Most Ubuntu users such as myself are quite at home with open source applications such as GIMP and Rhythmbox. Others still long for the day when Photoshop and iTunes will show themselves in the Ubuntu Software Center. Back in 2010, Canonical asked Ubuntu users to fill out a survey expressing which proprietary applications they'd like to see ported to Ubuntu. At the time, many Ubuntu users felt that this offered a glimmer of hope that these applications would someday find their way onto the Linux landscape. In reality, it led nowhere, and we won't likely ever see either application ported to Ubuntu.
Apple, for one, would sooner go out of business than bother trying to give Ubuntu a leg up with iTunes for Linux. On the other hand, Adobe is slightly warmer to the Linux desktop considering how many years they supported a Flash plugin for the platform. In reality though, I don't think either application is ever going to be natively supported -- at least not without heavy "social proof."
For example, take the recent PPA repository which finally allows Ubuntu users to watch Netflix on their Linux PCs, using a customized version of WINE bundled with Firefox for Windows and Silverlight. We see that Ubuntu users wanted Netflix on their computers so badly that they hacked together a workable solution. This produces a win for Netflix, as it will mean greater subscriber retention instead of further excluding their Ubuntu-using user base. And perhaps more importantly, Netflix now has social proof that Ubuntu users would be a worthwhile investment. In other words, it's time to lose Silverlight and use Flash like Amazon and Hulu do.
Each year I see new and exciting applications released for Android and on the cloud. In both instances, these applications either are or will one day be accessible to Ubuntu users everywhere. As the lines between Android and Ubuntu continue to blur, I believe that we'll see legacy titles finding their way onto Ubuntu via Android in the near future. I don't believe, however, that we'll see most legacy proprietary titles appearing on Ubuntu natively.
As for new software titles, I think that Google, among others, will continue to push the envelope in this the cloud computing space. These days, the Web browser is fast becoming the central point for software access to everything from accounting to Web conferencing.
One thing is becoming clear to me – proprietary software will indeed play a major part in the Ubuntu desktop of the future. The key question is, how beneficial will this be to existing Ubuntu enthusiasts? At this point, only time will tell.