Maybe they are the smart form of moron?
By the time it became apparant that the Wii was going to be a success (Holiday 2006 at the earliest) they had no relevant games to bring to the Wii in progress. Since most good games require a minimum of 18-30 months development with between 6-18 months of pre-production it would take between 2 - 4 years before any efforts started around the time of the Wii launch came to fruition. However since most games developers from publishers were already tied up for projects on the Xbox 360/PS3 and were halfway through development, the publishers best ROI would have had to have been to keep the good/decent projects on the Xbox 360/PS3 and any bad projects were probably scrapped and the developers refocused onto the Wii. Since these are poorer developers and given a time constraint to take advantage of the Wii success, comedy ensued aka shovelware.
By 2007/2008 it was apparant which studios were successful and which were not. The successful (good) studios were kept on task to release Xbox 360/PS3 content and still more average studios were probably tasked with Wii development. This is the point where we start to see better but not great content coming out for the Wii whilst the fewer battle tested excellent third party developers remained tasked with Xbox 360/PS3 content. This explains the content coming out in 2009/2010 and some of 2011.
Tease.
