Gizmodo has an article today comparing different types of razors under a microscope at the University of Oregon's Bio-Optics Laboratory. Not the most in depth piece, but I imagine people here would be interested.
http://gizmodo.com/5472426/razors-under-a-microscope
http://gizmodo.com/5472426/razors-under-a-microscope
Maybe some tools aren't old-fashioned. Maybe they're just perfect. The inevitable tapering toward only the necessary, the honing away of all distraction. The machine at its most simple. After that, what? Easy: mass production.
A razor is a wedge, one of physics' six force-multiplying "simple machines." Unlike the wedge used to split wood or hold a door open, a razor (and its father, the knife) do their work at their tip—the edge.
You know this intrinsically, but consider it again: The sharpest razor is just a few molecules wide at its edge, persuading the molecules it meets that it would be easier to decouple from their mates and let the razor pass through the space where they once twisted and wound together.
So if a razor is such a simple mechanism, why are there so many different types?
Perhaps the razor's simplicity lends itself to many configurations? A screw is a simple object, but there isn't just one type of screw, but countless variations to suit the needs of its user.
Or maybe there really is a difference between sharp and really sharp?