Southgate, new contract freshly signed, has taken the 3-5-2 formation about as far as he could, it's one playing style the team has grown into, but it's deficiencies have also now been exposed, now the time has come to move on, he hasn't been slow to bank that and develop another.
The signs change was needed were there in the defeat against Spain, and to a lesser extent in the victory against Switzerland three days later. They were getting penned in not holding possession and consequently not getting forward enough and scoring goals.
The flaws in the 3-5-2 system had become too obvious to him in reviewing the semi-final defeat by Croatia when a tired England side just struggled to control the game, especially in the second half. They now have the confidence and ability to pass the ball out from the back, and the cover of five defenders that ensured some leeway for errors, meant we suffered further up, switching to the four four two can alleviate that a little.
In the 3-5-2 we had scope to develop the passing game, bringing the ball out from the back with the safety net of numbers, but didn’t cover the pitch further forward, getting penned in. Harry Maguire and John Stones now know each other well enough to play in a different way, a back four when necessary.
One system is now embedded and has been taken as far as they possibly could, alternatives have to be developed and taken to the same level, so England can adapt and do both
Southgate has said that it was the right time for a change.
Against Croatia, they applied better pressure on their back four and on their midfield players. Our defence is no longer very new and the comfort of the five not quite so needed, there are signs we have learnt the lessons and are moving on.
There is very limited time, Euros 2020 will soon be upon us and he needs to get more men in advanced positions with confidence and ability to use the ball. Chalobah, Winks, Barkley and maybe or perhaps Loftus-Cheek or Foden, but don't pick anyone without enough first team football. There are others still very much on the fringes like Madison and even Mount, but they're nowhere near yet. Getting more in advanced positions is a start and a new formation can help.
The dependence on Kane isn't helped when Vardy rules himself out, Sturridge isn't playing often enough and Welbeck neither. Southgate still has confidence in Sterling and Rashford, who despite his troubles the other night, did score against Spain and Switzerland, and so retains his manager’s faith.
Southgate is reacting and he's doing it now. As with the build up before Russia 2018, the planning stage is a year or more before. Pre Russia, the 3-5-2 'passing from the back' revolution, the new progressive style was barely noticed by the usual perennial sceptics, there were still the predictably lame posts of 'Same old England' from those who barely even watched, and then so confidently argued 'we never change'.
We are moving on and in time.