Boutros on 07 December 2016
Final Fantasy is a franchise that used to cater to the casual gamer back when they owned home consoles in Japan but that gamer has long jumped ship for mobile gaming so what you're looking at is what the core fanbase of the series is. It's also why series like Persona and Metal Gear Solid didn't see a decline in Japan. Those franchises always depended on their core fanbase and never reached the kind of casual gamers that Final Fantasy did. So until that casual gamer is back on home console we can't expect Final Fantasy to reach the kind of numbers that it used to do.
