While Fox, Falco, Wolf, Falcon, Ness, Lucas, Nana, Popo, Mac, K. Rool, Banjo, and Kazooie are just happy to get another game.
It does seem like the Mother series is dead. I can't understand why Lucas' game was never released in the West.
Captain Falcon's franchise kind of got beat out by Mario Kart. I know they are very different but I think in Nintendo's eyes, they are both racers and Mario Kart is the more commercial successful of the two and gets investment as a result.
Star Fox received 1.5 games on the Wii U which is very recent (Star Fox Zero plus the Fortress stage). Star Fox played off a novelty which isn't present anymore. However, I do think there is potential with this franchise as flight simulators are not very common today. I wouldn't be surprised if we got a Star Fox game for Switch.
King K Rool is an interesting one. Not sure why he hasn't appeared as a villain in a recent DKC Returns game. Interestingly, he is still getting love with Nintendo, especially with the appearance in Smash. I think the future could be bright for him.
Banjo & Kazooie depends on Microsoft. Not sure why this franchise hasn't been reboot. The only guess on my end (and this is a stretch) is that perhaps Banjo doesn't fit the demograph of Xbox very well. Nuts and Bolts flopping didn't help as well.