Lots of History fans fetishize the Phalanx, but it had a ton of weaknesses. Which is reasonable in context, but some of these weaknesses seem pretty obvious in retrospect.

"Just shoot them and walk away briskly!"

"Go around the pointy bits!"

"Carry a big shield!"

Props to the Greeks and Alexander for winning battles accordingly to the phalanx's weakness.
Like phalanx does well when outnumbered in a direct confrontation, which is probably why it shined so well against Persia, which focused more on quantity over quality.

I guess tactics changed heavily towards heavy emphasis on cavalry & archery later on which is likely why the phalanx went out of fashion.
Though given that the phalanx could not really be piled on with more numbers, and usually phalanxes love to flank other phalanxes if they had more troops, I wonder if the famous battle against Hannibal at the battle of Cannae would have been different if such tactics were used?