At this rate, it might end the series, period.

Sales of FF and any game for that matter in japan is directly proportional to its install base.Relative to its install base (and those willing to buy a PS4 just for it) it will do well, question is just how well will that be in relation to its install base.

FF13 did well in japan, sold through to about 20% of the japanese PS3 install base. thats COD like numbers in say NA for the PS3 if looking at sales in relation to regional install base.

This leads me to conclude that what japan needs aren't just games like FF, but an overall cheaper console. When FF15 releases, if the PS4 is at around $300 in japan at that time, I expect it to do very very very well. However, this is still just one game. Lets see if deep down, MGS5 and bloodborne can spur sales in japan before FF gets there.

Could have the same effect that people are hoping Hyrule Warriors is going to achieve, cross the fanbases and result in higher sales for the game, I doubt it's going to happen for either game though, especially not for FF XV since I'd guess that there's a huge overlap between KH and FF fans.

Final Fantasy XV will do the lion share of its sales outside of Japan, but it might at least hit a million there as well.

The OP is completely out of touch. The problem first and foremost is the state of home consoles in Japan.

The real question is if -the few- upcoming AAA japanese games like MGS and FF will help improve console sales.

edit. the OP is also misleading if you notice the incredible attach rate of XIII compared to that of XII.

Kingdom hearts is not that big in Japan... lol. It's about moderate maybe but not big. You need to look again at the sales figures of the series. The PS2 ones were the only ones to really do great.

For me, YES

That's because the first two were released on the PS2. The PS3 only got the remakes, so there's no telling how KH3 would have done on the PS3.

Yeah, those were the mainline games...both 1 and 2 easily cleared a million, that's big for Japan, very big. If you don't consider KH big in Japan then you could basically say that Resident Evil isn't big either.

The two mainline entries in the franchise were the only games that did great anywhere, mostly because the handheld iterations were all nigh incomprehensible fluff.  I also think you need to adjust your expectations a little, because selling over a million in Japan is generally very good.  To put it in perspective, the two main kingdom hearts games in Japan have sold better than any of the various musou/warriors games, any tales of ______ (pretty much all of namco bandai's catalog really, tekken 3 just edged out kh2), any metal gear, any sonic game, any shin megami tensei, all but one resident evil (2 being the exception), most zeldas and on par with the rest, the list goes on.  It may not be on the top of the hill with pokemon and monster hunter, but not many games are, but it's certainly not moderate.

Not unless she can help it