Domains for Pokemon Lets Go Pikachu & Pokemon Lets Go Eevee registered by the same company Nintendo used to register the official Pokémon Sun & Moon website domain

[Lonely_Dolphin]

Ka-pi96 said:

Lonely_Dolphin said:

Game hasn't been revealed yet, but it has been announced that Gamefreak is making a core RPG Pokemon title for Switch set to release in 2018 or later. They said this last E3.

And none of that precludes the possibility that there are also spin offs in the works for either 3DS, Switch or both.

But it does mean Let's Go being a spin-off isn't a possibility like you said it is.