I saw this post.
Indeed like the OP said despite the Spartan Phalanx having the weakness of the right flank exposed, few city states dared faced Sparta in its prime out of few and those that did could not attack the right flank for whatever reason. Even when Sparta was declining, their enemies still refused to fight them face to face many times despite the right flank weaknesses and preferred newly discovered stuff like cavalry charges and javelineers doing hit and run tricks. And even than the Spartans could still win victories and inflicted heavy casualties in their defeats such as the Theban victories.
An even more consistent example is heavy cavalry. Despite long pikes being the weaknesses of cavalry, cavalry still won so much and dominated an entire era and it took adding more tactics than just holding long spears such as volleys to soften up cavalry by archers or crossbowmen and later gunpowder riflemen and building trenches and stakes on the ground. Even despite this, cavalry can still destroy a well-positioned army by charging in a direct attack, even bypassing trenches, stakes, and other fortifications and slaughtering troops holding long spear in a wall.
I am curious why despite learning weaknesses and having the tools to exploit them, elite units are still extremely difficult to battle and can even do curbstomping battles against forces attempting to use the weakpoints against the elite units (such as long pikes against knights)?
So many internet discussions make it seem like a Pokemon Rock Paper Scissors elemental game where water always beat fire pokemon, rock always breaks scissors, etc.
What is it about real war where its not enough to position troops on the high ground and shoot musket rifles at very slow heavy infantry trying to walk up the mountain to defeat your army? Or lightly armed archers defeating macemen in melee despite archers being weak in CQC because of minimal training and less armor as well as shorter and weaker hand to hand weapons?