Nintendo seems to be really struggling with making something for mobile that really sticks.

Remember that Pokemon GO is not actually made by Nintendo.

While I personally found Miitomo to be quite interesting, it was quickly obvious that Nintendo didn't really have any plans for it, and the question soon was: why am I "playing" this?

Nintendo is masters of the cute and weird, but do users really want a social media that makes it a chore to communicate with their friends, when Facebook, Twitter, Instagram and Snapchat makes it super fast and easy?

Seems not.