I'm just gonna go straight there: I don't think there will be a Final Fantasy XVI. Unless it's a replacement for XIV a long way down the line, but I think we've seen the last big budget single player Final Fantasy.

- For revenue, they have XIV.
- XV was successful enough that they think this is how you're supposed to make games now.
- XV was too much of a risky sunk cost to ever repeat. They're still making that game.

As bad as the XIII series was, it was at least an obvious misstep. Just 'don't do it like that again' is a pretty low risk way of fixing the issue. But XV? Lots of people liked XV, but lots of people hated its guts as well. It wouldn't have taken much to tip the balance unfavorably, and then it would have been a catastrophe. I don't see them taking such a high stakes gamble again.