I agree its about time we improve the way we interact with computers. The old Windows Icon Menus Pointing device (WIMP) paradigm invented at Xerox PARC is its reaching its limits. I believe that the 2 main factors that directly caused WIMP interface to reach its limits are display resolution and memory. 

Display resolutions have been increasing overs the years, although I do not have hard numbers to back up this claim, I remember back in year 2001, where CRT monitors were common place and LCD monitors were the latest in display technology. The average LCD monitor's size back then was just 15" comes with the resolution of 1024 x 768. Lets fast forward to today. Today, 19" is usually the smallest monitor you can find in store and typically their resolution is about 1440x900. More and more people are also expecting to get a monitor that is capable of displaying full HD videos, thanks to the marketing efforts of TV manufacturers. 

The problem with huge resolutions is that the cursor in the traditional WIMP user interface paradigm have to cover a lot more distance. To move the cursor from point A to point B across the screen should take roughly the same time no matter what resolution the screen is. To maintain both the same time it takes for the cursor to move across a larger screen, the speed must naturally increase. But increasing speed will reduce accuracy, so users will simply have to adapt. UI Designers tries to solve this problem by introducing resolution independent UI. What this means is that UI elements should appear roughly the same size on any screen regardless of its native resolution. Resolution independence is actually one of the feature in Mac OS X Leopard. That's why the default dock size looks roughly the same size on any Mac, any display. 

What about RAM? Its only till recently, the average consumer don't really have to worry about running out of memory anymore. Especially today, virtually every system (not counting netbooks) have at least 2 Gigs of RAM installed. Manufacturers also usually max out the RAM slots that are available on system's motherboard. Gone are the days where you can open up your system and still find spare DIMM slots for RAM. My point is that memory has gotten so cheap today. This actually changes the way we behave. We humans usually treasure stuff that are scarce, in the days where memory are scarce, we learnt to control the consumption of memory. Close any apps that are not in use, check and kill any useless background processes that suck up memory. In the not-so-distant past around 2001 the time when memory was still scarce and considered precious, most people would have at most 3-4 apps running at the same time and would not hesitate to close them when they threatens to slow down the system.