I never understand this prediction. That's a bit like saying I don't need a car because I could just dock my bicycle into some sort of enclosure with four wheels. Tablets, smartphones, and laptops/desktops were all built for different purposes and cannot be full replacements for each other, just like a bicycle can't fully replace a car without some serious sacrifices.
What if an iPad Air could simple attach to a MB Air chassis and only serve as the display when attached?
Android is a bit better than iOS in this respect, but not much.
None of the mobile vendors have any incentive to change this, since it would mean forfeiting the App Store tax and for Apple would cannibalize the Mac market. The only way I see an uncrippled mobile device entering the market that is high enough quality to compete is if someone with none of these conflicting interests bucks the trend. Android is pretty forkable, so a droid fork that solved the security problems in a non-feudal way and that supported the sort of docking you describe would be disruptive.
Dell? Compaq? HP? A "washed up" PC vendor with stagnant market share would have nothing to lose and might have the resources to pull it off.
The App Store "tax"? Sure, Apple doesn't mind the cash. But they are first, second and third a hardware company: that's where the real money is. The reason they have no intention to allow side loading apps on iOS has to do with user experience, eliminating support headaches and security (order may be different, but these re the reasons).
The fact is your dream device would appeal to the same people who buy desktop Linux machines now. They exist, but they are a tiny part of the market. Nobody can stay in business catering to just those customers.
In 5 or 10 years dockable tablets are going to be every-goddamn-where, especially in business. It just makes sense, and is too all around practical. And for most computer uses, even "intensive" ones, it's perfect. You get portability plus productivity in the docked configuration plus huge economic benefits. Tablets are mostly just screens, batteries, and a handful of chips, all of which are super amenable to economies of scale in manufacture. Tablets are going to be cheaper than dirt eventually, and because a tablet can be a self-contained computer it'll tend to be the default computing choice. The biggest thing missing today is primarily good software.
I would instead focus on the work done with virtual machines. If instead I had a subscription service to access a virtual machine that had the ability to run any application I wanted, streamed to my mobile device that would then display it anywhere I wanted. My mobile device could connect me to any amount of computing power I need (in reason and with a large enough budget).
Why on earth would I buy this whole separate machine to do this? My personal computing device that I carry around with me everywhere could allow me to perform any function possible, I could have a full desktop computer anywhere I wanted as long as I have a internet connection and a screen.
Gaming could take place anywhere as well. You wouldn't need a gaming rig, the processing power would be handled elsewhere whilst your device handles the graphics processing and streaming.
Internet speeds will have to increase exponentially, but are we really that short sighted to state that personal computers will never be replaced by mobile devices? Yes it may not happen tomorrow, but it will come
