I think most RPGs are multiplatform nowadays and/or "better on PC" (because of mods and such), so it's tougher for them to be a traditional system seller. No fault of the genre or the games.
RE: 3DS support, keep in mind they also said they were going to continue to support the Wii U, and had no plans to stop production, until the day they announced they were stopping production. It's possible they keep the 3DS around as a low cost option (apparently the GBA continued on with third party kiddie games after the DS overtook it), but I think Nintendo's "big" titles are going to be transitioned to the Switch going forward.