2017 was awesome and all, but it's no good blowing your load too soon.
Nintendo themselves have acknowledged that a big part of Switch's success was a steady stream of heavy hitters over its first 9 months; they needed to continue this pattern into 2018, not go back to one major title every three months like in the Wii U days.
What heavy hitters were you expecting? Mario, Zelda, MK and Splatoon has already been released. Release Pokémon and SSB in the first half of 2018 and whats left? Animal Crossing maybe.
They needed to make an impression in 2017 and they did. There are still many games coming. They may not be AAA, but its WAY better than what the WiiU usually got.