I won't say 3rd parties can't sell on the Wii, but I think most of the comparisons don't prove much of anything.
Why? A few reasons.
Install base. Sometimes in the examples the author says "well, X Wii game sold as much as Y PS3 game" even with a almost 2x install base.
Release date. Some of the games (madworld and bayonetta especially) are released at drastically different times.
Game library. The PS3 and 360 have a decent amount of FPSs where as the Wii doesn't have as many. You can't expect a relatively not well known fish in a massive ocean of FPSs (Timeshift) to sell as much 1 of 5 fishes in a tiny aquarium (The Conduit).
Numbers. Sometimes it seems like the author is pitting WW numbers versus regions numbers of other games (I might be wrong on this one).







