Now this is a pretty interesting post, knives have always been a hot topic, and ask any woodworker, sharpening is an even hotter topic--Iv'e seen fist fights break out concerning oilstones and waterstones and bevels.
I have to disagree about steels, or "butcher rods". When properly grooved,(not worn out) they work. It's all about orthodontics, straightening teeth, or in this case the edge. Every time you use the steel you should wipe the knife blade, or you'll get black crud on the first slice you cut. The black crud is tiny bits of 1 micron sized peaks of the edge that have failed and boken off. If you were to view a razor blade edge under a micron microscope, you would see two planes meeting, and at the point where they meet, you have the cutting edge. This edge is very thin and with use will curl over. The steel with it's grooved ridges, will grab and straighten out the edge, but it will eventually fatigue and curl over again. When this has happened too many times the two planes don't meet anymore, and you get a rounded edge, or a dull knife. The only thing to do now is to re-establish the two planes, or bevels, so they meet again and this can only be acomplished with abrasives.
A pro will use a linisher, or narrow belt sander. The belt won't heat up the blade like a grinding wheel can, won't shrink and change diameter like a wheel can, won't break up and fling pieces of wheel at around 100 mph at your face, and are cheap and easy to replace. But the pro also knows how to put an apporopiate bevel of the knife and to shape the knife's edge. If the knife's profile has a hollow in it, if you can see light peeking between the edge and the board it's resting on, then you'll never be able to completly cut through something. If the profile is flat, then you can't rock the knife, which means you'll have to lift the knife with each cut, resulting in fatigue and a far greater chance of injury because you're lifting the knife up and have less control over than you would if part of the knife is still on the board.
The bevel, the bevel, the angle at which the two planes meet is just as critical. If the bevel is steep, the edge will be extremely sharp but very weak, if it is shallow, it will act like an axe, strong edge but a tendancy to split rather than cut. If the bevel is inconsistant, areas of the knife will dull prematurely. The pro will adjust the table on his linisher and put a consistant
bevel on the blade. Many cooks claim they can put a bevel on their knives with stones, but achieving a consistant bevel freehand takes a lot of time and skill to develop. Gawwd knows how many "sharpened" knives Iv'e seen with scratches up and down the sides, with flat spots and hollows, broken tips rounded over, and $60 stones glazed up with vegetable oil (never do this). A jig,or gadget, is needed to ensure a consistant bevel, the pro has a table on his equipment for this, and the woodworker his jigs to ensure his tools have the proper bevels. Call it what you will, but if you don't have white hair and a long beard, chances are you can't do it freehand with a 8 or 9" blade on a 8" x 4" stone.
The whole purpose of using finer grits is to remove the scratch pattern left by the previous grit. A blade sharpend with a 100 grit stone will look like a pair of cordaouroy pants under a microscope. Big deal? Remember an edge is two planes meeting. If both planes are ridged, than the edge will look like a comb, with fragile points ready to fatigue and break off. The finer grit you go to, the smoother the surfaces of the planes, and the more durable the edge. Woodworkers take their tools to 6 and 8000 grit, the pro's will use a honing compound to get knives to this stage, but the scratch pattern should be as smooth as possible. I have never seen a cook yet take his "sharpened knives" to this stage, which is why he is constantly "sharpening" (and shrinking) them.
So forget all the hocus-pocus and glossy mag adds about cyrogenically hardended steel, carbon steel, space age steel, what-ever. Get the bevel and shape right, use a jig, guide, or gadget to ensure this, the abrasives as fine as possible, and use the steel inbetween.