Microsoft's Distinguished Engineer Eric Traut talked about and demonstrated MinWin, which is a project to create the most efficient Windows kernel that will in turn be used as the core for the next Windows platform, called Windows 7 for now. It was part of a bigger presentation at the University of Illinois, and so I'm only linking the part of the video that specifically relates to Windows 7 and MinWin. Get the video here.

As computing keeps plugging away (sorry for the pun), code and programs will keep getting more wasteful as resources and computing power are cheap and plentiful. In the old days when CPU power was at a premium and ram was expensive and hard to come by, programs were compact and efficient.

Having spending many years on IBM Mainframes, I can tell you that there are more
lines of code in Windows that on the mainframe.

More lines -> bigger modules -> more complexity

Q.E.D. Bloated