I've been working with computers for 20 years - long enough to remember when pundits said no average user would "need" the awesome power of an 8 MHz 80286. Nope, that kind of raw power would be reserved for things like servers. I can remember the same lame argument being made for every new chip from the 80286 through the Pentium Pro. Finally, the so-called pundits got it through their heads that quite a few users would buy the latest chip because they wanted to regardless of whether they "needed" it or not.

Needs do vary over time. Back in the late 1980s, most average users were content with an 80286 system running at around 10 MHz and sporting 512-1 MB of RAM and a 20-40 MB hard drive. Most people didn't even have VGA monitors, either. I actually got into a heated discussion with a coworker (an engineer, no less) who wondered why anyone would need the power of a 80386.

Windows 3.0 changed all of that. While still inferior to Apple's MacIntosh, millions of users decided that Win 3.0 was good enough for their needs. However, Win 3.0 demanded more power than that typical system I described above. Nope, running Win 3.0 on an 80286 was possible (I did it for several months) but painfully slow. You really needed an 80386 or even one of those powerhouse 80486 chips to get good performance. 1 MB of RAM? Forget about it! While Microsoft claimed you could boot Win 3.0 with 1 MB, you really needed at least 2 MB, and 4 MB was much better. You also needed a bigger hard drive because Windows apps were bigger than DOS apps. Oh, yes, you wanted a better monitor and graphics card, too.

Like you implied in your post, Windows is a CPU sink. It can absorb whatever CPU you throw at it. Whenever a new CPU design comes along that makes Windows run too fast, a new Windows version will be released to absord the extra power. This forces people to keep upgrading their systems in order to maintain a reasonable level of performance. I've often said that the computer hardware manufacturers of the world should line up in a public square and take turns kissing Bill Gate's butt. His Windows products have single-handedly caused millions of people to spend a lot of money every couple years on new hardware to keep up.

Of course, most of that extra power is being absorbed to create better user interfaces and more capable systems. Back in the CP/M days, a user would buy a copy of dBase II for $495. When he booted the system, his user interface consisted of a single dot (.) on the screen. He had to program everything in dBase using dot commands. Contrast that to today's database systems.

Switching from a command line interface to a GUI required a lot of CPU power. Doing everything in graphics mode requires a lot more CPU power than text based output. Throwing in things we take for granted like TAPI, MAPI, browsers, etc. also demands more of the system.