Not a difficult prediction to make. No one's actually expecting the Xbone to reach Xbox 360 sales, 360 is the best supported MS platform ever and it barely made it past the PSP. Xbox is losing the market share it captured from PS last gen. Nintendos hardware business is dwindling, the 3DS has peaked, mobiles changed the handheld industry forever, the next Nintendo handheld will likely have trouble reaching even the 3DS sales. Same story with their home consoles. Nintendo consoles sold less each gen since the NES if the Wii is left out.
I find it hysterical the way you and other Sony-posters have to pretend like the Wii didn't exist to make yourselves feel better when talking about Nintendo. (Not that it matters to Nintendo. I'd rather profit off 22million Gamecubes than lose my shirt/break-even selling 80 million PS3's too.) Anyway, my point is, it would be like if in every post I were to pretend the PS2 didn't exist and look at the video game industry this way:
You're right. Ignoring the existence of one entire product really does put a different spin on the industry.