The base formation for the USMNT under Berhalter has been the 433. That’s been unchanged. If you look around the world at some of the best teams, many seem to have the base of a 433. Man City, Liverpool, Real Madrid, Bayern, Barcelona, Ajax. Why is this structure or formation so popular?
I have a theory.
Formations and systems are trendy. It wasn’t that long ago that the 4231 was all anyone had been playing. In the last year, we saw a heavy use of 3 in the back systems across the major teams. Tuchel went from heavily using the 433 at PSG to using a 343 variant at Chelsea to great effect.