I see where Pachter is going. Making an AAA game on Wii - assuming it's a traditional console game like Left 4 Dead - will not likely make great sales and not the type of sales developers would be looking for, for that type of investment.
3rd Party games that sell 1m plus are (by and large) more casual in nature and a great many of them get to that total at reduced prices (Lego Star Wars). In comparison a game like L4D should easily break 1m on HD consoles at full price.
Most successful 3rd party games are well known (and by well known I mean known outside of gaming circles) brand from Star Wars and Resident Evil (both movie franchises) to Deal or No Deal to Dance Dance Revolution and Guitar Hero. Even Call of Duty fits that mode as it's big enough even non-gamers have heard of it.
A Grand Theft Auto game would sell reasonably well as it's a well known brand to everyone (whether they played it or not) but almost any other 'known' gaming IP is still unknown to the Wii audience.
With Nintendo, EA and Activision taking 65% of the Wii pie, that doesn't leave much for everyone else considering how many titles there are on Wii.
If I was a developer I'd either go for a Boom Blox type game (fun and accessible for all) or find a dedicated niche to mine like NMH is doing. I sure wouldn't put a God of War type and quality game on Wii.