Because we need to be able to counter quickly and its easier to source players with pace and the composure you mention than play possession based footy as you need a better quality of playmaking skill and all your players to be comfortable on the ball, such as City have to be effective. And that costs big money.
Of course not only pace is enough but in this league pace can be a weapon look at Forest and Palace in the semi, they use raw pace on the counter attack of course you don't want headless chickens but we really don't have enough pace, especially in wide areas, its partly why our counter attacks break down. We also don't have composure you mention either the amount of attacks that break down due that, Doucoure or Beto are two examples but also we need someone in midfield who can dictate and with the vision to pick out players.