The return of endpoint should be an array, not an object, to maintain the endpoint pattern of launches.
This resolves to cases where there are more than one future launches.
Next and Latest can only return a single launch, so no array is needed
Past, Upcoming, and All launches can have more than 1 launch returned, so an array is used
I think you're looking for the /launches/upcoming endpoint, which has all the future launches. Next and Latest are just convenience endpoints for getting the most recent or the most upcoming launch, without sending unnecessary extra data.
@jakewmeyer Certainly, thank you.