Will any more consoles be added to the NSO service?

[Soundwave]

Yes but I think disc based games (Dreamcast, GCN, Wii, etc.) will have to be handled differently, as in like you will be able to download your "favorites", but having every game downloaded won't be feasible because it'll take too much storage space.

Also the other complication may be that Metroid Prime Remastered sells so well that they go "hold on a sec, we can charge $50 a pop for remastered versions of these games".