I wouldn't say that all those downloads are lost sales, if any of them really. It could be that there are only about 800,000 pirates downloading everything, and that's not as bad as I thought.
That chart is a list of the most popular games for those who don't have price/value issues affecting their decisions.
That could mean that while Punch-Out!! and House of the Dead Overkill are both amazing games desired by a great many people, most people don't think they're worth $50 because they're just too damn short.
Or it could mean that Wii pirates at torrentfreak.com only like sequels. I can't believe more people would steal Mario Power Tennis over Metroid Prime Trilogy or MadWorld or Muramasa or something.