Since Nintendo announced a Mii player in Mario Golf and a Miitopia port for the Switch a few days ago in a direct, my hope for a new Tomodachi life game was very much strengthened. If and when could that come out?
Well, at the moment they're also working on the Switch version of Miitopia, so it's not that unlikely that a very popular DS game will appear again. However, I don't know whether the game genre makes so much sense in connection with a console that it can actually be implemented. You would then have to incorporate additional elements / aspects that would make the game console-worthy and that will definitely not be so easy with Tomodachi Life… So if at all then with a lot of luck only in 2 years…
Very unlikely in my opinion.