In a year of COVID delays, Nintendo has announced a handful of games recently, including Super Mario 3D All-Stars (a collection of 3D Mario games), Super Mario 35 (a Mario-themed riff on battle royale), and Fire Emblem: Shadow Dragon & the Blade of Light (a localization of the first Fire Emblem). Those are all different games from one another, but what all of them have in common is that Nintendo will stop selling them on the same date: March 31, 2021.
This is a companion discussion topic for the original entry at https://www.vice.com/en_us/article/jgqxay/nintendo-will-stop-selling-multiple-games-in-march-2021-but-why