Personally, I first of all see software moving from desktops to the web (and becoming more "rich" and interactive in the process). What's the point in waiting a year or more for an upgrade to office 2007 when I can get daily upgrades via a web app (I am thinking
www.37signals.com here)? I also see it going mobile. The latter has already begun in some respects. I however don't see it being the only platform. Trust mankind, something else will be invented that will make our kids say, "Dad, you used mobile? Man, that's soooo 2008!

"
As far as deprecation, that has also already begun - think of C code written in the 60s when memory was a big deal and think of code now. Having said that, I see software being more english-like (I am thinking Ruby here). Whether this makes "everyone and their uncle's donkey" an app builder is another story.
Finally, as with other human inventions (mechanized agriculture, industrialization, etc), I see software going back to its roots - in the past, US farmers did practice leaving land fallow. Due to industrialization, they started using fertilizers. Now that those same fertilizers have been linked to cancer and pollution of water tables, to mention but a few, many farmers are now talking about returning to, "the old ways". I see software following the same trend. We will do all we can to it but at some point, critical mass will be reached and someone somewhere will say (and make a ton of money off of it too

), "man, something is fundamentally wrong here! we need to get back to the basics".
As always, my 2 cents.