And i too say its pretty possible that the switch 2018 sales can decrease because the lineup wont be that good like 2017. There wont be a new Zelda, Splatoon or Mario ( including kart and rabbits ) this year aka 3 of Nintendos biggest titles ever. 3rd party games wont move much untis lol even when they bring pokemon and animal crossing this year, what have they left for 2019?
I feel like this has been repeated ad nauseam, but there's 2D Mario, MK9, 2D Zelda, Smash Bros, Pokemon remake (Ruby/Sapphire sold like 12m on 3DS). Pretty sure Nintendo would do an Odyssey 2, and a follow up to BoTW wouldn't be out of the question. That's just their top tier. We also have 2nd tier stuff like Bayonetta 3, Metroid Prime 4, Kirby, Yoshi, Arms 2, Pikmin 4, Donkey Kong.
Rockstar has been working with Nintendo, rumors have a GTA V port coming, so possibly GTA 6 will make its way to Switch as well.
There's so many possibilities, while I don't think Switch will do Wii numbers (the hype was insane for that, I dont we'll see that type of hype for a system ever again) I do see around 80-85m for Switch.
The fact that Switch did so well at $299 with no deals for the first year is such a positive sign for the future. Once they start price dropping and bundling, the momentum will increase IMO.