According to Masahiro Sakurai in a video uploaded to his YouTube channel, the game started out as a requested NES adaptation of Kirby's Dream Land, but Sakurai and HAL Laboratory successfully negotiated with Nintendo to make a new game in the series for the home console instead, which became this game. Sakurai also said he and his team wanted this game to be on the SNES, but they simply didn't have the money or resources at the time as HAL was also on the verge of bankruptcy.
Contributed by PirateGoofy
Video