That a European distributor forced this into a contract with Atlus is the only explanation that makes even a little bit of sense to me. I don't fully understand why Atlus would sign it, unless they're deaf to the constant howls of impatience from their European fans.
Shifts in exchange rates mean that Japanese software prices that were roughly at parity with US ones at the start of the current console generation now look incredibly expensive by US standards. At the same time, it's not like people in Japan are suddenly getting paid way less, or it's gotten cheaper to develop a game like this in Japan, or that they are going to drop the cost of all games in Japan purely due to external factors.
Like it or not, this is a game in a fairly niche genre, based upon another (admittedly more popular than most) game in another niche genre, that also happens to be a Japanese game. The primary market for this is Japan, and that's probably were they're looking to make most of their revenue on the title. The problem is that the ludicrously strong yen has lead to a significant increase in the reverse importation of entertainment media back into Japan from other territories - particularly the US - where it's suddenly gone from being slightly cheaper to being way, way cheaper. This is why a number of Japanese anime labels have recently been making moves to revoke or deny Blu-Ray media rights to their foreign licensors, and why Funimation aren't releasing the likes of Panty and Stocking on BD.
This is probably normally less of an issue, but this is a fighting game being released in the US real close to the Japanese release. Language is rather less of an issue than it would be for, say, an RPG, and the fact it is a fighting game means that they've been able to get it localised so quickly (it wouldn't shock me if, region lock aside, the US and JP disks have exactly the same software on them, multi-language for everything). The alternative is probably that they'd release the US version months later, and that'd just end up leading to just as many, if not even more, complaints.
Not trying to defend region locking or anything (or say that European partners have nothing to do with this, just presenting the alternative plausible argument) - I mean, I'm a Brit myself, so this stuff effects me. Someone in Japan is probably seeing this as a necessary evil towards actually being able to turn a profit on developing a niche HD-generation game like this, rightly or wrongly.
(Anecdotally, on the subject of it maybe being a European partner issue, I do know that one of my local gaming chains imported a whole bunch of copies of the US PS3 release of Catherine well in advance of the EU release, which also meant that they basically ordered in zero copies of the EU PS3 release when it came out. That had to suck for whoever release it over here).