It might surprise you, but not everyone is the biggest fan of indie games. There are some I enjoy a lot, but a lot of them do not appeal to me due to the gameplay and graphics being inferior compared to the games they are inspired from.
Nintendo makes great games, but I tire of buying Nintendo home consoles just for Nintendo games when I am also a huge fan of third party titles which I miss out on because of their relations with said third party.
Nintendo fans will always purchase Nintendo consoles because they make, well, Nintendo games. I'm a Nintendo fan, but not in that way. I want something that caters to a wider demographic like the DS and 3DS do.