I disagree, but I also think your a bit uninformed.
3DS is a different console, it will be tracked differently from the DS.
However the DS Lite, and DSi are essentially remodeled DS consoles.
The only difference between the DS Lite and regular DS is size, my friend owns a DS lite, and I own the original, and thats all there is to it. It's no different from a 360 Slim or PS3 Slim
As for DSi, it's a DS Lite with some new features, like a Camera, and the ability to download DSi games. Since DSi games are DLC only, VGChartz doesn't track them, had they, sales would be tracked as DSi games. The main purpose of the console is to play DS games though, and essentially it's still a DS Lite, just with a camera. This is no differnet then the 360 bundled with Kinect, and we still track those 360's as regular 360's.