I'm not saying they don't count. Clearly the numbers do. But there's a difference between friendlies and the World Cup.
The big players didn't perform when the chips were down. That is precisely when their experience and composure was supposed to give them the most edge. Broad was particularly insipid. I genuinely cannot believe that Joe Anybody from Durhamchester wouldn't have produced at least an comparable performance. Obviously he's miles better than Joe Anybody, and he's started (comparatively) to show that now. But it's too late. If you're going to talk positively about their mental characteristics, then the state of the series is a critical element of the situation.
Again, I'm just talking about the bowling that I watched. When the pressure was on, Anderson was unthreatening and Broad insipid. The only real exception is Adelaide II (already discussed), and even then, an England win was already a wildly unlikely proposition even if they knocked us over for half that total. Both significantly improved once the pressure was off.
This is not a reflection of their skill at all. But you'd expect players with all of that composure and concentration to be at their best under pressure. As it was, Overton was the bowler who emerged with real credit.