In real terms this is about mainstream Western success. In the RPG space when FF was at its zenith on console FF was in a way the only game in town, as WRPGs were still the frontier of the hardcore PC niche. These days, FF's biggest rivals aren't things like Persona (much as JRPG fans like to loudly play up Persona 5 vs FF15 this year and will continue to do so) - FF's shot to regrow its audience to FF7/8 levels - basically, to attract more causal RPG fans - sits in showing off well against its rivals, and its rivals in the marketplace now are things like The Witcher, Mass Effect and Elder Scrolls.
There's a reason why people like Tabata and Kitase have talked a lot about looking at those games throughout the 13 sequels/15 productions, and it's because that's really their target audience, at least in the West. They have a solid audience of 4-6 million fans who are likely to buy so long as the game isn't a disaster regardless of what it is, so the question then is growth beyond that. In this sense I think there's absolutely still a battle for FF's soul going on even now, and I think that's exemplified in elements of how FF15 has been discussed by the developers - they used the term 'open world' a lot early on after the 2013 reboot, but then in the last 18 months or so have back-pedalled from that terminology with "It's open world-like, but..." -- they're still figuring so much of that out; what FF was versus what it needs to be to stand alongside those games and hopefully attract their audience. In some ways they're stuck between a rock and a hard place, too, as they're trying to open new doors in the West but at the same time if they push too deeply towards action Japan might rebuke -- but put in too many concessions for turn-based stalwarts in Japan and they'll struggle to be on par with their Western peers, and so on.
Dragon Quest doesn't have that problem; it's unlikely to become much beyond a quality niche commodity in the West anyway. I think DQ and things like Setsuna will find a solid market as turn based thing, but I don't think main line FF will ever go back unless the market significantly shifts. Even if Setsuna sells a million or more, which'd be great for a game like that, it isn't going to move the needle on that front. It's not so much about FF 'doing its own thing', it's about FF chasing the large Western audience it found and (mostly) held between around 1997 and 2000 again, and to do that they've clearly decided it needs to be more like a lot of the Western stuff in the genre.