I don't think you get my point, though. To me, demos are supposed to look awesome even on slower hardware
How does one define "slower hardware" on a PC? A 486DX, or the budget GeForceFX cards? Both can be considered slow from certain perspectives.
Contrary to yourself, there are people in the PC demoscene who complain current productions don't use enough new features found on the Radeon 9000 or GeForceFX series. It really is a different scene from all other platforms, you're just going to have to accept that.
Try the GameBoy Advance scene, that might be more your style.
- compare for example The Castle, Little Nell or Relic running on AGA and a 50MHz 060 and a demo that requires a 2.2GHz P4 and a GF4 Ti4200.
But these are just relatively simple (by today's standards) 3D flybys running at far less than 60 fps in super low-resolution. Your graphics card can easily run demos similar to this at 1024x768 @ 60 fps.
Okay, I know this is a flawed comparison, but take Relic. It runs at about 160x120 @ 30 fps with an '060 @ 50 MHz. To run it at 1280x960 @ 30 fps, which contains exactly 64 times more pixel surface area, would essentially require 64 times more computing power. 50 MHz x 64 = 3.2 GHz.
Of course this is a pretty flawed comparison for obvious reasons, but it does show that PC demos aren't as slow as you seem to think.
Of course the PC demo should be fast! Where did optimization go?
Optimized like games? They now take several years to develop, a few dozen staff, and millions of dollars. What demogroup has those resources?
Making a good demo with modern hardware requires a much larger precentage of time devoted to design. Moppi Productions only produce one demo a year, and their code seems far from optimized. Yet the design, content, and style of their productions is quite startling. Stunning stuff.