This was a Nintendo Direct Mini.
Maybe, there's a possibility they are not going to announce the entire lineup in it.

Who knows.

Weren't they exlecting to sell 20mil Switches in 2018?

There's likely a ton of things left for the first half of the year.

It's possible they're holding back a lot. Keep in mind this was a mini direct fresh in the new year. The game's just begun~

This year will most likely seem lackluster compared to last year, and it's off to an okay start

Definitely hope they have some big announcements for mid-late 2018

Based off history, having all this success so quickly could end up hurting more than helping because traditionally, the leader of the market gets lazy. Nintendo may start to think they don't NEED to do this or that and then, we're at their mercy. I hope they keep their foot on the gas though. They really can't afford to rely on ports and B-games.

Just because one MINI Direct? Overreact too much

Nintendo is notoriously secretive about what they have in production. For all we know, there could be another game or two for Spring we don't know about yet. They're not going to stuff all the good stuff at the end of the year leaving Summer dry. We'll get another Direct soon to clarify the exact 2018 lineup.

Did you intentionally miss all the "coulds" and "mays" or was it accidental?

I don't think this mini direct is everything for the first half of the year. I expect the Switch has a lot more coming than this.