It's because knowing that they're going underpowered has meant, since the Wii, a forced wacky novelty. Even the DS series, great games abound, started off slow with a bunch of forced touch novelty, and although I had a great time with some of those games, I still somewhat resent the dual screen and touch.
At this point, power doesn't mean much though. I don't need Uncharted 4 graphics in a Nintendo game. I would sure love it if the consoles weren't consistently sold on a novelty though. And while I'm cautiously excited for switch, I can't help but feel like they've already set themselves up for failure, in some sense. Just the idea of switching controller forms and having to have full sized controllers or half sized and sliding on and off and .. Bleh. I hope I'm pleasantly surprised.