Market data shows that home consoles are not affected by the growth of the smart device gaming market. But it does show that dedicated game handhelds are taking a hit.
http://www.mobile88.com/news/read.asp?file=/2011/4/19/20110418192208&phone=iOS-Android-gaming-increase-market-share-US
Android/iOS share of US portable game software revenue up to 34% in 2010. Nintendo down to 57%. PSP down to 9% (ouch).
Dedicated handheld game consoles are on the decline (But they will always be around and have their audience). At least for this coming generation. The mass market does not want watered down home console gaming on the go. That's basically what the 3DS is (apparently N64/PS2 ports with a tacked on 3D gimmick is supposed to sell the 3DS) and Sony doesn't seem like they are learning their lesson by putting watered down portable PS3 games (ie. Uncharted series) on the NGP. The Japanese third-parties like Capcom, Square-Enix, etc. will carry the NGP just like they did the PSP. There is a base out there that is excited to play Uncharted on the go. But that game will lose a lot of money for Sony. The DS was a hit because the games were suitable for mobile gaming. To be honest, I'm looking forward to seeing the 3DS fall short of Nintendo's projections and Nintendo's revenues going down at the end of the fiscal year. The gaming industry operates with the mindset that gamers are stupid and will buy into any cheap gimmick. Perhaps a lot of gamers are stupid. I certainly feel like that sometimes. But I don't think the expanded/lapsed gamer market is as stupid as Nintendo thinks. If they were truly stupid, the shovelware would have carried the Wii through this really long quality software drought. But it's not.
As for home console gaming thriving despite the existence of PC gaming. It's simple. Console gaming is more accessible, user-friendly and convenient for the mass market. Smartphones don't have the same accessibility problems that PC gaming does.