That's isn't exactly true. They may not have the genre power that they did a few years ago, but since WRPG went the console way, they have been more mainstream in the RPG genre, competing with JRPG's and garnering more fans from that side of the genre. But there has been lot's of indicators too, that JRPG's are still as well accepted as they have always been, especially in Japan.
Taking out the account that they do poorly on the 360, the most singular case that you have is ToV which had the strongest opening week of all Tales games in the past years, on a system which had the lowest user base in the past years as well.
As I said, there are a lot of factors that cannot be mislooked in this kind of predicitions, especially since we're talking about a genre defining game like Final Fantasy.
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CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
