You have to consider that most of these advertising groups are geared towards sales conversion.
To most YouTubers, getting a few thousand views could be pretty cool but isn't going to make or break your channel. But a few thousand page hits where you're selling something, maybe 10-15% conversion, that ad cost sure makes a lot more sense.
They're not designed for people trying to make making videos a career.
Like that DollarShaveClub video. Not to mention the viral views from just being a great video... They probably pay $0.03-$0.10 per view via ads. If even one person signs up with their $1 a month thing, they cover 120-400 video views.