Using the "Wii games are cheap because they are all shovelware" argument is crap, as is always the case when you argue extremes. No one says that Wii games cost pennies to make, game development costs have been rising since the inception of the industry and with complexity of hardware.
If you want to play the shovelware card then you need to compare apples with apples, and yes shovelware does exist on the HD systems, just in smaller numbers. Shovelware exists on the Wii in larger numbers than the PS2 because of the co-existence of two factors; large install base and cheaper development. The PS2 had the first factor but not the second.
Here is a recent statement from one of the largest, and lately one of the more promising third party developers out there.
"EA's John Riccitiello has made a strong argument for why EA is looking to increase its Wii development. It boils down to the fact that developing for the Wii is a lot cheaper than for other current-gen consoles. Riccitiello said during EA's Q3 2009 earnings call that "development is typically a third to a fourth as much for a Wii game than it is for a PS3 or an Xbox 360 game." When put like that, it's a wonder anyone develops high-definition games at all.
Riccitiello went on to explain that this is largely due to Wii developers "producing less art than for high-definition games." As a result, EA will be giving the Wii as much developmental emphasis as the 360 and PS3 enjoy collectively, seeking to "rival Nintendo on their own platform." If the announcement of Dead Space for the Wii is any indication, more emphasis will also be put on bringing more hardcore experiences to the console, rather than ports of the latest Madden or block-based puzzle games."
(sorry, close the link, will track it down later if anyone wants it)
People have now provided several articles showing that Wii development is GENERALLY cheaper than development on the HD consoles, i am yet to see a single article from a developer saying that costs are equal or even close.