And Wii still had Zelda: Skyward Sword, Mario Galaxy 2, Wii Party, Xenoblade, and many other big titles in the 2nd half of its life cycle ... same thing with 3DS, the thing is you run into diminishing returns by about year 4 with most Nintendo systems because the fan base for those games in large part already has the system.Â
3DS sold 7.27 million shipments the fiscal year Sun/Moon arrived, that's really not a monster boost and that was more likely due to Pokemon Go being such a phenomenon on mobile to boot.Â
Wii sold 100m not really a good counter argument especially as Wii's 4th year was one it's best for releases, Tatsunoko vs Capcom, NMH2, SMG2, MM10, Red Steel 2, MH Tri, Sin and Punishment 3, Guitar Hero, Epic Yarn, Goldeneye, DKCR etc... The Wii had come from 3 prior insanely good years for sales so it's a given it was going to slow down it was in something like the 70m region heading for 80m and even with sales slowing down it was still outselling the competition.
You're arguing that because a series is already present it can't push sales Sun and Moon being the only major release for that quarter moving 7.27m debunks this as under what you're saying Pokemon should not have had any impact even with PGO because the fans should already be on board from X/Y fact is it doesn't work that way.