One up front with 3 attackers behind is not much different from playing 2 up front. In many ways it's more attacking. It's also the way we won the league last season.
Footballers aren't on the woodbines at half time and in the pub after training anymore. As such, the formations are way more fluid.
Ask any coach. Even the colts play various formations, but usually anchor things to a 4-2-3-1 because it's so adaptable.