like tears in rain.
I can name a few reasons.Yup. XIV was understandable though; still, 2.0 made up for it in spades anyway.
1. Those three games all bear long scars from the tenure of Square Enix's first post-merger CEO, Yoichi Wada. I don't believe Wada alone is to blame, but considering the preferred method of solving problems at his time was "throw more money at it lel", it's not hard to see the pattern. That's how SQEX gave us two sequels to XIII; "we blew a truckload of money on this, might as well make good on it."
2. A huge chunk of XIII's development time was, in fact, devoted to its proprietary engine: Crystal Tools. In the meantime, the developers at Business Division 1 just couldn't figure out in what direction to take the gameplay; it didn't even have a battle system until The Powers That Be™ forced BD1 to make a demo for the FFVII: Advent Children Complete Blu-Ray.
Add to that some public-relations blowups (passing PS3 screenshots as X360...) and a localization that blew a huge chunk of the story to the ground, and you have... one of my favorite FF games, actually, but it drew a lot of heat from just about everyone else.
3. You already know what happened with XIV.
4. Oh boy. Ignoring its vaporware history as Versus XIII, XV somehow repeated many of XIII's wounds. It was supposed to be made by the Kingdom Hearts II developers, then was abruptly passed on to Business Division 2 (Type-0) on another proprietary engine (Luminous Studio), while somehow repeating several of XIII's development wounds—down to the Episode Duscae demo, which was bundled with Type-0 HD and played very differently from the final game.
The script was still being heavily rewritten months before release, which probably made the story a lot messier. Finally, SQEX put out a plethora of badly-advertised tie-ins; and a "live service" formula that ended in the game's director quitting, and half its DLCs being cancelled and stuffed into a book. One PR disaster after another, oops!
The XV developers, now without their old director, are soldiering on at Luminous Productions and its as-yet-untitled Project Athia; I honestly hope they'll be okay.
If XIII got more heat than it deserved, XV got a volcanic eruption. It was a development so disorganized and excessive, it's probably not something anyone involved would rather talk about.