What do todays operating systems do that is too hard for people?! You manage files, you install programs, you work, or play games etc. It's dead easy! My grandfather, who is in his eighties just got a Windows 7 computer and loves it.
Computers are not hard. This is marketing spiel for "buy our dumbed down product." Remember I buy all of this stuff too. My iPhone is sitting right here, I have an iPad and I work on OSX. I'm not against these devices per se.
If desktop OSes mostly go away, what will people be working on? Accountants? Engineers? Researchers? Programmers? Editors? Designers? This is all just frivolous stuff or what? The last time I checked, people who were actually productive are the ones making the Earth "go 'round". Apple is pushing a vision of constant entertainment consumption, and minimizing how important productivity is in every respect.
I can fully believe in the future our desktop machines could basically be something like 5mm thick iMac style machines with perfect screens, massive storage, and incredibly powerful cpu/gpu etc etc. Whatever. That's not the issue. The issue is Apple removing capability from an OS and pushing it as the future. Nothing iOS does is all that special. It's a compromise to run a decent OS on a small device. That's it.
Remember, OSX is still around 5% worldwide share. If they abandon pro users, then the entire ecosystem dries up and vanishes. Why? Because you need a decent machine to make apps for their toys! Certainly MS will keep pushing productivity and cost effectiveness. Apple is pushing high prices, and form way, way over function.
Something, at some point, has to give.