Are you sure you know which is the real shovelware though? For example, would you be as critical of "Carnival Games" as "Shrek's Carnival Craze"? One of these is not actually shovelware.

yea I know the difference between a game who's target audience is children and a game exploiting parents lack of knowledge. But in the end most games designed for children could be considered shovel-ware.  Mostly what I see are parents who pass up good titles like mario kart for games like M&M Racer

I'm not really sure why attach rate is cited as an issue for Wii. Shipment data, which is more complete than Vgchartz data or the data of any tracker because it has to be government approved, shows that in the Americas Wii has a 9+ attach rate - probably slightly more even if you included downloadable games. Worldwide, the attach rate is 7.6, and through September that was 429m games or something shipped lifetime.

Look at the data through Sept (this is off the top of my head) and you see that basically half the Wii market is controlled by publishers making four types of games:

The Essential Wii Quadruple: MK Wii, Wii Sports, Wii Fit, Wii Play total ~120m units of SW shipped

Big Nintendo Games 60m-70m?:

Brawl (9m), Galaxy (8m), Zelda (5m) Wii Music (3m), Excite Bots (2m), Metroid (1m), Punch Out (1), Fire Emblem (1), WarioWare (1), Wii Sports Resort (7m), Wii Fit Plus (1m), Play on Wii series (4m), Mario Sluggers (1m), Mario Strikers (1m), Mario Party 8 (7m), Animal Crossing (3m) I'm probably missing a few others

So in total, I don't think Nintendo has more than ~43% (185m/429m) of the Wii software market. For small third parties, another ~12% of the market is locked off.

Music Games: 15m-20m

Guitar Hero III (4m), GH: WT (3m), RB (1.5m), RB2 (1m), B: RB (1m), GH5, GH: Aerosmith, etc all add to it

Party Games 25m-35m:

Mario & Sonic 1 (7m), Rayman/Big Beach Party/Carnival Games/Cooking Mama and a bunch of other have done well

Fitness Games 10m-15m:

EA Sports Active (2m), Gold's Gym (1m), Jillian Michaels (1m), etc

To me, these above areas are basically off limits except to a handfull of publishers, mostly Nintendo, Activision, and Ubisoft. But if my figures are correct, those four proven types of game only account for half the market. Some other content has succeeded too, because even with half the market controlled by the games above, ~200m other Wii games sold in the systems first 34 months. Capcom, Sega, Konami, EA and a handfull of others have all had multiple titles top a million units on Wii that were not Music, Party, or Fitness games.

Super expensive core games will never be made for Wii because publishers only get ~$28 at most back of every $50 a customer spends on a game. You can get like $38 back on a PS3/360 game. So if you sell a million copies on Wii, you get $28 million - $4 million, $24 million. If you sell a million on PS3/360 you get $38 million - $10 million. It is more profitable at the million + level to make PS3/360 games with relatively modest budgets than it is to make Wii games. This allows Nintendo's content to dominate above the 2m unit level, while at 1m-2m its closers to a 50% share, and below that third parties dominate at a 60-70% clip which is enough to make good money, just not blockbuster money.