I can't answer for Mr. Smith, but I believe he was the first to put forward the observation that flat-nose solid bullets cutting a wound channel not much bigger than one inch give optimum killing effect in medium and larger game. Also that jacketed expanding bullets often kill more slowly, even when fired from heavy magnums and making much bigger wounds tracks. He certainly was the first to promote this concept actively, because if someone else noticed it first, they didn't do much to spread the word. Just look at pre-LBT mold catalogs and cast bullet designs.
Mr. Smith's observation seems counterintuitive until you know two things are true: The first is that a flat-nose solid cast bullet is more likely than other designs to completely penetrate the game and leave good bleed-out holes on both sides.
The second is a biological curiosity: Nature has figured out survival chances are enhanced if small cuts and wounds bleed freely enough to wash out most of the germs. But for large wounds free bleeding causes blood loss to be more life-threatening than sepsis. For this reason the body tries to distinguish between the two extremes, and when a wound is clearly large, releases hormones that shut down the capillaries and stem bleeding. This is why someone may bleed to death from a .22 hole though the leg, but survives having the whole leg taken off above the knee in an accidental encounter with a Great White or other heavy equipment (though, necessarily, not in that order).
Unfortunately for survival, but fortunately for hunters, nature is unable to draw a very fine line between the two wound sizes, leaving the optimum wound channel size available to exploit with hunting loads. This is what Mr. Smith's various wide meplat bullet designs do. If you need proof, visit the catalogs of his mold-making competitors today and count how many now have near copies of his designs. 15 years ago they didn't. You won't get the same quality from them either, but I suppose any attempt at imitation is an indirect compliment.