That doesn't dismiss my point. Neither Pokken or Detective Pikachu are anywhere close to MH4 either, and yet those two spinoffs have been continued, so obviously it's not just that which influences their decisions. If Mystery Dungeon checks off something they want to do and they consider it worthwhile, they may do it, not selling as much as MH will be a complete roadblock.
Also, you're still relying on the same fallacious argument here. No matter where the sales come from, you're trying to compare games of different franchises, genres, and otherwise that even the companies themselves are likely not (or at least have not said) using as a base guideline. TCPi is likely not looking at the sales of MH4 and saying 'nope, Super didn't sell that much, failure' just as much as Nintendo didn't do the same for Metroid Samus Returns, IS for Fire Emblem Echoes, and so on. They likely have their own expectations for the game and judging based on those expectations, not on another company's game that is almost completely unrelated to their own and basically has its own level of success.
