Yes, but... why lose all the extra functionality if you don't have to? Even if 90% of the people aren't using a PC to its full capacity it is better to have the capacity than not. I think that is the much stronger human nature than the to accept change because you have no other choice. After all, how many people need the performance of modern cars? How about 4K TVs? I can't even tell you how many people I know still use RCA cables or tune into non-HD channels on HD TVs and are happy with the picture and think they are watching HD. Yet they all still want more.
I have a hard time seeing the majority of people choosing a lower performance restricted device over one that offers everything when all other things are equal (if Intel power use comes down to ARM levels and Core chips get 8+ hours battery life). Already people are clamoring for Tegra 4 RT's and way more powerful top shelf gaming power Pros
In part, I agree.
However, the only reason we make this distinction - like the one you make in terms of extra functionality, lower/ higher performance etc. - is because we know about the alternatives. But just think - in a few years, this distinction, which is already being blurred, will be further eroded and then there is the question of economics. For example, a Bentley is a fine car to have. But in my hands, it will do the same thing as, say, a low-end Buick or Kia (or whatever). The only difference is that the Bentley costs many times more than the low-end affairs. Today, I may be able to afford to rent the Bentley for a month, but with the same money I can probably own the Kia! This type of a scenario will get further exacerbated as the global financial situation stumbles from one crisis to another. And with it, our collective earning power will decline. I see this happening here in the UK (and in certain parts of Europe). This will compel us to look for the best bargain.
And then there is the paradigm. I think what is eventually going to happen is that there will be a convergence of the tablet and the computer - what MS calls the 'hybrid'. I really think this is the short-to-medium term future of personal computing devices. For this, a unification of the OS has to take place - Windows Blue is an example (allegedly) of MS working towards this end. It is clear that the Win 7 type OS interface will not work on an ultra-ultra light platform - otherwise MS would have made a killing with their convertibles a long time back, isn't it. Win 8 works to move the PC paradigm in this direction and Windows Blue is supposed to be (again allegedly) that which takes that even further. Now, what is the device that is most amenable to this emerging state of affairs? I'd argue the RT. It has the least legacy-related baggage and it forces the user to think differently. Not so, in the case of the Pro - as I mentioned earlier. This is the reason I think that the RT is the more revolutionary of the two devices.
My caveat? Hey...I am just a normal run-of-the-mill user who is speculating on this stuff. I have no real insights into this industry and can only report anecdotally on the stuff that I see and hear happening around me, which is very limited in many ways. So, I stand to be corrected.