>>38522
>Why late roman army didn't reintroduce the phalanxes

Greeks/Macedonians didn't won any decisive battle against Romans in war, maybe only in first year. So, phalanx wasn't that good.

Considering "phalanx" in broad sense, i.e. tight formation of heavy infantry - Romans already had it, even in times of Macedonian war (they had maniples etc). Only real difference is long spear, but looks like it proved itself not so good.

>limitanei, feodorati could use the formation

These two categories weren't best in their training and skills, considering their purpose and composition. I guess they weren't good in formations that require discipline at all.