Nintendo has made a lot of games throughout the year, for both Switch & 3DS, for just 2018.
- Pokemon Let's Go Pikachu/Eevee
- Super Mario Party
- Mario Tennis Aces
- Kirby Star Allies
- Sushi Strikers
- Warioware Gold
- Detective Pikachu
- Dillons Dead Heart Breakers
- Smash Ultimate
- Nintendo Labo Kits
And next year, they have a lot on their plate already; with Daemon X Machina, Fire Emblem Three Houses, the Traditional Pokemon title, Yoshi, and a lot more.
To say that they aren't producing a lot of 1'st Party games, is a bit insulting..
Also..Retro isn't working on Prime 4; and the current consensus in rumors is a Singapore Studio with partnership of Bandai Namco (similar to how they are doing Smash Ultimate).
Depending on when they'd do it, it isn't like they don't have a supplier that doesn't have enough games to justify an event for Universal Park's & Resort's.
I would like to add on, that with the endeavors that will be made with the Southern Property; it'll be allowing hopefully a good amount of growth for that entire area around it, for better or worse.