Perhaps you're thinking having a change of goalkeeper is like having an involuntary change of quarterback, which I know from my limited knowledge of NFL can be a disaster for a team. But it's not, it's more like a change of FG kicker. Disadvantageous but not enough to move the line by more than a cent or two. Most team's second choice goalkeeper will be world class and little worse than the first choice. Of course it did mean they couldn't use the substitution more constructively, for example to put Messi on! Germany do have a reputation for winning penalty shootouts, but frankly that sort of statistic, formed over a limited history, is just something to make the other side (unless it's England) a little bit of value.
