Actually, from working at Gamestop, I find lots of parents buying their children under the age of 6 a video game system. I assume for most reasons it is to "give them something to do/out of their hair", but also it is a mainstream form of entertainment and they are going to ask for it. Whether it is responsible or not for a parent to buy their child under that age a gaming system, is up to the parents themselves and no one else. My personal opinion is that gaming won't harm them as long as parents make a point that it can't become a center of their life. Need to say this is just A form of fun they can have while also pushing other kinds of games including ones that involve physicality outside.
Now for those that do buy it for that age group, 90% is that of a DS. And if they are looking to get them something else, I usually tell them not to. DS is easily the lowest maintenance system on the market. And by using cartridges, there is no worry of scratching discs. A great things about the DS was also how easy it is to use and operate compared to the other systems. It also has a large game library that is catered to less reading-intensive games and even a large variety of educational games. So DS was and still is a viable system for that market.
Now will 3DS turn away that market? It's really doubtful as there isn't a stigma by parents against 3D movies. I mean most of the movies made in 3D are catered towards kids and kids that age see those movies, in spite of the "usual" warnings. So I doubt the 3D aspect will actually change that in parents. And I still think the system will be viable for that market, as parents are going to stick with the brand they know is good for their children and Nintendo has been that brand. But once again it will be up to the parents to make sure they are playing in moderation, taking breaks, and seeking other activities.
As for the pricing, this may have some affect as parents don't want to buy young kids something too expensive out of fear of them breaking it. But it is doubtful young children will be of the early adopters. When this age group starts buying it, it will probably have gone down in price.
