Forging is more flexible in terms of what you can achieve. Forging also refines the structure of the steel.
Drop forging and rolling does indeed impart some of the benefits of forging to a stock removal blade, however. once you start grinding away material, the grain is interrupted and any benefits are minimized or lost.
Forging, and in particular, low-temperature forging aka austenite forging, allows the grain to follow the shape of the steel to an exacting degree (assuming a skilled smith). I personally austenite forge all of my blades. That involves forging the steel below its critical temperature (before it loses its magnetism at the critical temperature). Grain growth due to high heat is minimized and the steel gains tremendous toughness and edge-holding ability. My hammer blows are precise and the forge-finished blank has a smooth surface.
After profiling and forging the tang, the edge bevels are forged and before finishing the blank I go over every blade surface with a series of rapid, precise, and hard hammer blows to really refine the steel grain structure. I have taken years to refine my hammering technique to achieve very specific results. Each alloy needs to be handled a little differently and you have to understand how to work the steel you are using.
When I heat-treat, the steel is brought up to the critical temperature slowly and held only long enough to reach an even temp, then quenched in the appropriate medium, usually peanut oil or a mixture of 10w30 and transmission fluid. Tempering is done immediately. All blades are differentially tempered for a harder edge and softer spine and tang.
There are records of blades being ground back in the 13th century using massive wheels powered by water. I have seen some grinders claim that this is proof that stock removal makes a perfectly good blade and has a long history, what they neglect to mention is that the other half of the woodcut shows smiths FORGING blades! They are obviously using the wheels to rough grind and polish blades.
I do not have a degree, but I entered into this craft with an open mind and looking at everything I could find on the subject. I have done and continue to do as much research as I am able. My experience has shown me that aus-forging really works well. My guess is that those who claim it provides no benefit either have not done it or haven’t done it right. Some displacement of steel takes place of course. It has to, but they are ignoring what happens to the grain during this lower temp forging. This minimizes grain growth and maximizes the benefits of forging.
I have heard it argued that the only thing that affects a blade’s quality is the heat-treatment, not forging. But I must point out that if forging didn’t have some benefit, why is it that virtually every world-renowned chef, woodcrafter, and collector specifically desires hand-forged blades? Why is it that in every engineering manual it discusses the benefits of forging, whether by machine or by hand, as being grain refinement, allowing the grain to follow the profile of the item which increases the shock absorption and strength of the piece? Why do my hand forged blades withstand a significantly larger amount of abuse than my ground blades? They have the same heat-treating, are of the same steel and have identical dimensions. Yet without exception, my hand forged blades outperform the ground ones in all respects.
Why is it that for the parts that human lives are depending upon such as in airplanes, the parts are forged? In my experience it is preposterous to assume that forging provides no benefit.
Stock removal can make a sound and durable blade. Period. No question about it. Stock removal relies entirely on the alloy properties and the quality of the heat-treat. I have not, nor will I ever say that grinding a blade cannot make a high quality blade. I do say that proper and skillful forging can create a superior end product. Will most people notice the difference these days? Probably not. Does it matter to me? Absolutely! My objective has been and always will be to make the finest quality blades that I am able and to me that means starting with forge, hammer and anvil.