Well, if we think about it this way....
OG1 and OG2 were literally released on the GBA's deathbed.
OGs and OGG were neglected because of the profit would be less than what they would pay for the license, VAs and overall, the game itself.
Endless Frontier sold less than expected, really slightly more than enough to pay for licensing.
And why was this? Because of lack of promotion. I saw no banners on gaming websites, I saw no announcements, I saw no TV ads. Also consider how most fans of the series know it as Super Robot WARS, not Taisen.
The terminology pretty much widely known. Heck, you can find the majority of the stuff on TVTropes or Wikipedia, even YouTube videos. That's how simple it is.
The only thing I could really congratulate Atlus on was the localization and actually attempting to bring the series to the West (Mind you, this was before the big craze about Persona 3 when they were actually willing to take risks) Considering NISA's pretty much SRPG heaven right now, with games like Disagaea (Sp?) Z.H.P and some of their recent titles (Blazing Souls, Sakura Wars, etc) being SRPG/ Visual Novels, I can totally see this working to their advantage. Didn't Atlus release the first Disgaea game?
The things that NISA does differently? They a) actually promote their games, and b) give you a straight answer and are nice about it. I can totally see NISA making a buck considering they are better than Atlus in the publicity department. Plus PS3 isn't dying a la the GBA and DS were when Atlus released EF and OG1/2.