Leader of Jigglypuff Army
Anniversary celebration games are also a pretty recent standard within the past decade. It didn’t really start until the Wii Super Mario All Stars Collection was ported to the system and the Four Swords was put up for free in the eShop to celebrate Zelda for a limited time. After that each major anniversary became a huge deal with Nintendo with a few series that played an important role in Nintendo history like Metroid or F-Zero have gone by unnoticed.Because sales.
Hype up a game on an anniversary of what is arguably the biggest video game brand name on the planet, and it's guaranteed to sell a few million copies.