Find me a reasonably reliable example of a close-combat fight during wartime between two opponents who were equally well trained, rested, motivated, healed, and equipped, but of significant difference in height and reach.That is pure myth...and a dangerous one to cling to, especially, for example, in time of war, old sport.
Every single detail and decision made in a war is an effort to ensure that all is not equal once the fight starts.
Some things matter more in a sword fight than height and reach, yes. Which is why I started that sentence with "ALL ELSE BEING EQUAL." That phrase is important, and you don't get to discard it. If the ONLY difference between combatant A and combatant B is that A has a two-inch reach advantage, that reach advantage will be deterministic.
Such match ups are, of course, extremely rare, even in a sporting contest where the situation is arranged to be as equal as possible. Almost all the time, one person will be more skilled or more motivated, and that tends to make the difference unless the size disparity is extreme.