F-Zero is because Miyamoto can’t figure out what to do when Mario Kart 8 specifically took on the role of F-Zero with the anti-gravity and 200cc additions to 8. F-Zero needs a reboot / gimmick to separate from Mario Kart 8.
Star Fox has long been plagued by the derailment of the franchise from Star Fox Adventures. Nintendo has attempted to remake Star Fox 64 and reboot Star Fox 64 so as not to revive the series (the latter only failed because Wii U and hardcore gamers refuse to leave comfort zones). In fact, Ubisoft’s use of Star Fox couldn’t do anything. Star Fox is as good as dead. Maybe Nintendo can try to reboot the series again in 30 years (Nintendo will re-release Star Fox 1, 2 and 64 in the meantime).
Kid Icarus is mainly because no one is available and if anyone was available, no one has made a successful pitch for a new Kid Icarus game. Sakurai has temporarily revived the AI franchise, but he doesn’t want to return to this franchise. Uprising had good sales but it had heavy criticism of the controls and Nintendo might feel like re-releasing Uprising on a newer platform with better controls and better multiplayer balance won’t be the answer to the interest in Kid Icarus breathe new life into it.
All other small IPs are IPs that only met or fell short. Some of Nintendo’s new IP addresses from the 3DS era are missing for Switch. Mallo and Pushmo have not been seen since Wii U / 3DS. Sakura Samurai hasn’t had a new game since 3DS. There are many other examples.
If no one buys these small titles, Nintendo has no choice but to make Mario, Mario Kart, Zelda, and Smash Bros. games (with the occasional Pokemon game from The Pokemon Company). Yes, that means buying games you don’t want, such as Paper Mario: Origami King and Star Fox Zero (Wii U).
By not buying small games and games that change the formula or have nontraditional controls you see Nintendo in a third party production role they do now (after all, people always wanted Nintendo to become a third party and now we see them in a third-party production frenzy with few games outside of Nintendo’s primary AAA games).