Whether large amounts of protein are needed to build muscle or not, high calories (at least higher than maintenance) are. You can only get calories from three places (alcohol aside): Protein, Carbs, and fat. I prefer to get the largest share of my calories from protein, since it results in a better metabolic profile for maintaining muscle/not gaining fat. There are also long-term health issues that can be associated with higher levels of fat or carbs, so protein ends up being the default calorie source.
I'm not going to spend time digging up all the studies on this (you can if you wish), but I can tell you my diet of the past ten years had tended to be much higher in protein and much lower in carbs that that of the average American, and it has always produced great results for me.