Blaming Nintendo is definitely a stretch, though I do understand where they are coming from even if it is a poor argument. 360 and PS3 both have decent sized chunks of the industry, and if the truth be told they were the ones sustaining most of the sales the previous years since most Wii titles that sold well were Nintendo published. You would maybe see a couple of Wii games in the sales charts, most were 360 and PS3 games if I recall correctly, so it honestly makes no sense.
Hardware sales are approaching their peak with willing buyers as well. Wii has sold millions upon millions in the U.S., and has pretty much reached market saturation.