Part of that is because mobile gaming largely sucks, and Nintendo doesn't want to be associated with something that sucks. So their entry into mobile is much more cautious and calculated, intended to present the kind of experience Nintendo is known for rather than the usual sort of IAP money farm that is commonplace in mobile gaming.

The approach of Sega, Capcom, and Konami was to pivot from traditional games into money farms, and that sowed a lot of ill will among their fans.

Try playing Sonic Runners. It's sort of okay for a while, then it hits the wall of "spend money or be forever in grindy hell". It's like a stripper who's very friendly with you for 30 seconds, then starts asking for money to keep being friendly.

If Nintendo did that, it would take a power dump all over their brand. So they're playing it safe and taking a more measured approach to mobile.