There's a very real chance that The Conduit, Deadly Creatures, Madworld and House of the Dead Overkill will flop in sales...if they don't get a big advertising campaign.
The fact is I see multiple 3rd parties spending loads of money on their PS3/360 hardcore titles in regards to TV ads and instore promotion. If companies don't give their hardcore Wii games the same support..then yes..they will bomb.
I would love to see Sega do very well from their games....but I doubt all Sega's hardcore games combined will have close to the advertising budget spent on Mario & Sonic at the Olympic games.
Marketing is crucial.
Having said that..I don't think it will make a difference in regards to quality western support despite what some may claim.
If these games do well you'll just see devs get their C grade studios to make poor quality rushed hardcore games as opposed to poor quality rushed casual games.