Their handlhelds usually have better games then their home console counter parts. Why that's the case is another post. Pretty much every Nintendo handheld is universally loved while the home consoles are hit and miss for some. I mean how many people consider the Wii U a better device then the 3DS? Very very few. A lot of people say the DS is one of the best consoles of all time while the Wii is seen as good or even excellent but inferior to the DS.
Quality sells consoles and Nintendo handhelds are just better made than their home console counterparts.