I thought I would try and give my (simple) version of how teams evolved towards the box Midfield & why it helps teams dominate possession. Below is the basic 4-3-3 that caused teams that defend in a 4-4-1-1/4-4-2 shape a problem. The 8s picked up positions in the half spaces.
If the defending team looked to close off the half spaces it may then have been possible to play directly into the CF (who may drop deep into the false 9 position). Think Pepβs Barcelona side. He also used this in the recent Manchester Derby (at the Ethiad).
Defending teams eventually figured out that a narrow Midfield 4 plus a player on the DM could make it difficult for the 4-3-3 to progress the ball. Possessions were often slow & sideways (passes to full backs ‡οΈ).
What then happened is Managers like Guardiola (at Bayern) started to push their Full Back slightly inside, opening up the passing lane directly into the Winger. This helped bypass the oppositions narrow midfield 4. You can kinda see a box developingβ¦
The next evolution was full backs (like Lahm) inverted into a proper Midfield position, with the DM moving across to create a double pivot. Now the opposition have a problem as their AM is outnumbered (and this drags out another defending Midfielder, creating space).
If the defending team try & play any kind of 4-3-3 their DM is outnumbered. It is almost impossible to cover the 4 Midfield players (the box) using a Midfield 5. There tends to be space somewhere on the pitch.
Which leads us to the current set ups. Most defending teams now drop both forwards onto the attacking teams DMs, who then have control of the game (CBs are free). This is how I have witnessed the evolution anyway βπΌ