I'm not going to quote Verendus's giant post, but I'm trying to make sense of a multiplatform release if a key goal is to grow the PS4 userbase in Japan so that SE can move future PS4 games. Why would consumers buy a PS4 for DQXI if it's available on a platform they already own like PS3 or 3DS? As we've seen with past PS3 and PS4 multiplatform games (not to mention Vita/PS4 games), the sales split is rarely in favor of PS4. So it must be a PS4 exclusive to accomplish this goal, but Verendus keeps talking about platform splits (also laughing). How do we reconcile these things?
Answer: it's a timed exclusive. Consumers can't buy another version if it isn't being sold yet. SE is no stranger to taking money to sit on a version of game. Further, SE has ported the last DQ mainline game all over the goddamned place, even to where it barely makes sense (3DS).
So, SE puts out DQXI on the PS4 and hopefully reaps the benefits of that arrangement (western sales, increased profile internationally, domestic PS4 userbase). Then they scoop up the stragglers in six months after they jam the game onto 3DS. And then they keep jamming the game onto more platforms because they spent a lot of money making it and they can.
This, however, makes everyone happy, so I'm probably completely wrong.