I have entirely switched to my laptop, but when I'm at home, I hook it up to my larger monitor and keyboard. My prediction is that mobile devices will actually fill this niche, allowing you to consolidate to one computer, but effectively hook up to a more comfortable setup at home.
Desktops will still exist, if only because they will provide the latest and greatest technology, but for people who don't need the horsepower, a mobile device should work just fine. Laptops almost strike me as the worst of both worlds: crippled hardware due to form factor, but still too big to comfortably carry for most of the day.
I fully expect an iphone version 8 which docks into a dumb terminal, and runs the same apps as when mobile, with the same data. So you have mobile-text editor, dock, and you get OSX (OS11?) with a full screen that we're used to for desktop text entry. Undock and your data is all still there as well, with an interface optimized for mobile reading & edits.
For example, an x200 or x200s can comfortably give you computing power with a decent dualcore processor while weighing under 3 lbs. Obviously, you can't carry it in your pocket, but it's just about as portable as a frisbee. "Too big to carry around for most of the day" no longer applies with a laptop like that.
Sorry, by "too big to carry around for most of the day", I basically meant in my pocket. My laptop is fine for carrying around if I know I will want my laptop, but my phone comes with me regardless. I can't imagine taking a laptop to a party or out to dinner, but I do this all the time with my phone. As such, I interact with it in a totally different way, and it allows me a huge amount of freedom.
There are certainly a lot of computers out there that are no hassle to carry for most of the day, but it's still a conscious choice. It seems to me that the final barrier is the decision to carry it everywhere, not just anywhere.
Desktops will still exist, if only because they will provide the latest and greatest technology, but for people who don't need the horsepower, a mobile device should work just fine. Laptops almost strike me as the worst of both worlds: crippled hardware due to form factor, but still too big to comfortably carry for most of the day.