While this is probably the case in the US, from what I've seen it isn't the same here. Of course networking matters and recently there's been some articles in the newspapers about girls being worse off because they focus on grades instead of networking, but I also know that grades/being at the top of your class is very important. This is mainly based on job ads and people I personally know, where being at the top of class landed them the best jobs (while probably knowing the right people at the same time).
Also, personally I won't be studying at a business school.
Network is far more important and used than you think, most of the people I deal with, who work in finance all know each other and have worked together previously.
Sorø and herlufsholm are basically giant $30k a year future business networks.
Most nice jobs never get posted, they get filled via network.