Or ... Publishers could just recognize the popularity of the Wii and design some games around the Wii running at 480p @30fps, and then release versions with higher detailed models and textures that run at 720p @60fps on the HD consoles. Its really not a revolutionary problem being that (for years) PC game developers have produced games that targeted the systems the typical user owned, while providing enhanced visuals for PCs that were only owned by a handful of people (or that weren’t even available yet).
Consider a game like Half-Life 2 which ran on the original XBox, and yet it takes a system similar to the XBox 360/PS3 to play at its full detail, at a high resolution, with a constant frame rate at or above 60fps.