They can enjoy lower than GameCube sales then if they want.
No one is forcing them to lower the price, the market place just doesn't care about the system and I don't think another Mario platformer and a direct sequel to DKCR is enough to bring in tons of people. There's a lot of redundancy in their lineup too with the three biggest games all being mascot platfomers (NSMBU, Mario 3D World, and DKC: TF) but that's what they're going to have to try and work with.
Maybe without Mario Kart this Christmas there's no point really, it's not going to sell like gangbusters either way, so yeah, maybe they should just pocket the extra profit from Nintendo fans that just have to play Mario 3D World and move on.
The other problem is Nintendo fans are basically conditioned to not pay a lot for hardware as Nintendo traditionally makes cheaply priced hardware. And coming off the 3DS, a lot of people are not willing to jump in because they feel the same thing is going to happen again, the Wii U is actually selling quite a good deal worse than the 3DS ever did.
My personal feeling is MS will cave on the XB1 price too and drop to $399.99 just before launch to match Sony.