Similarly, how I determined whether Bravely Second was successful was based on relativism as opposed to the actual numbers. We have no idea what the development budget or promotional budget was, but knew the game had debuted a lot lower than Bravely Default, which was bad. We also knew that handheld games with similar sales volumes rarely ever saw sequels at Square Enix.
However, this wasn't a guarantee of meaning, and simply an educated guess based upon trends. The thing that ultimately solidified its lack of success was Asano saying he was immediately going to submit the plan for Bravely Third if the game was successful enough, and then shortly after release, saying they were trying to decide if it made more sense to try another sequel or to try an entirely new game instead.
Without this type of commentary, we could simply analyze the situation and makes predictions, and then wonder for years if we were right. Right now we still don't even know if the game was profitable, and this decision was made simply upon it not being profitable enough, or if it actively lost money, which would help inform future discussions much more. We also don't know what types of platforms the team might work on next instead, which would give us some more hints at the implications of not having enough success.
Obviously Terra Battle WiiU + Last Story Remastered.