Such grouping of men orientated their arms and their efforts to attack in the same direction and, combined with the hoplites' morale and cohesion (reassured as they were by their comrades' proximity), allowed them to defeat larger but less organised armies (as at the Battle of Marathon).
Grouping men in this way, as well as the use of the pike returned at the Renaissance (Flanders and Swiss mercenaries) to face royal armies with a strong tradition of heavy cavalry (France at the battles of Courtrai and Burgundy at Grandson then Morat).
Also, Machiavelli (Discourses on Livy) theorised on the use of long pikes to arm the city militias of the small merchant states of Northern Italy (in some of which the beginnings of a citizen-body were apparent).
From then on, the ordre serré was only used for riot control (CRS and Gendarmerie mobile), or to order and move large bodies of men, or for parades (notably that on Bastille Day).
Infantry fighting thus based itself on two concepts : The English preferred the "ordre mince" (thin order) and had even developed salvo firing by sections, which allowed a group of men to (on each volley) create a gap in the opposing formation.