Of course that is true if you're talking the last 5 years. Simply because we never had the players to play 4-2-3-1 properly until last season. Actually, I should stress that most of the times we have played poorly it was because it was a 4-5-1 with three central midfielders.
Now that we have Carrick and Anderson, we have the players capable of playing 4-2-3-1. And using that formation we've destroyed Roma (although Giggs played that game rather than Anderson), Arsenal and Newcastle, and completely dominated Lyon (and only wasteful finishing stopped that from being a much bigger scoreline).
The key difference is obvious, and I find it ridiculous when people lump both under the same 4-5-1 banner. 4-5-1 has three central midfielders playing in the middle of the park, with two wingers and a striker who invariably gets left alone. Whereas a 4-2-3-1 has two central midfielders staying deep, two wingers and another player (either an attacking midfielder who can run at people and create for others like Anderson or Giggs, or a deep lying forward) all buzzing around behind the main striker. Basically there is one extra player attacking. But strangely so many people say that if that player is nominally a midfielder it's a 4-5-1, but if a forward plays that exact same position they call it a 4-4-2. In reality, 4-2-3-1 when used well has the best things from both formations. The midfield control of 4-5-1, and the attacking verve of 4-4-2.
Basically, we did to Lyon what Milan did to us last season. Complete domination, harrying them off the ball the instant they got it and not letting them build anything. We didn't use the ball as well as Milan did, but that was mostly because Anderson had a bit of an off-day. But we still dominated them, and if the final ball had worked for us we could easily have scored 4.