Whatever happened to good old 4-4-2
https://www.amazon.com/Inverting-Pyramid-History-S...
Basically the structure of the 4-4-2 isn't good for dealing with teams playing 4-2-3-1 or 4-3-3 - you get outnumbered in crucial parts of the field. Seeing as those formations are popular 4-4-2 became less popular