The team behind The Legend of Zelda: Breath of the Wild opted to create a sequel rather than an entirely new Zelda game due to the amount of DLC ideas it had for the 2017 original.
Speaking with Kotaku, series producer Eiji Aonuma said DLC was a great way to "add more elements to the same world" as Breath of the Wild, "but when it comes down to technical things, DLC is pretty much data — you’re adding data to a preexisting title. And so when we wanted to add bigger changes, DLC is not enough, and that’s why we thought maybe a sequel would be a good fit."
When asked if the sequel was initially planned as an expansion, Aonuma said the team was only brainstorming DLC ideas at first, until it became clear they had greater ambitions. "This is too many ideas, let’s just make one new game and start from scratch," he said.