It would seem so and, IMO, it is the single most predictable failure of the year. Yokai's appeal, it's charm, so much of it is culture dependent. Not related, dependent. The whole premise's charm comes from Japanese folklore. The odds of something so dependent on the local culture would have any success in the west was slim at best. Add to that a battle system deliberately aping the simplicity and style of popular mobile games in Japan - something that just doesn't fly in retail games in the west - and failure was almost assured. Pokemon's success is largely due to it being its own context. Sure there were and are Japanese influences but the fact is you have no need to know anything about Japan to get the appeal. Yokai has its own merits, sure, but so many of the charming touches come from an outside context, the Japanese culture. And if you don't know the culture, you won't get it.