Disgaea being a sleeper (I'm not even sure it deserves that title, but whatever) is a bigger deal on the ethers of the internet than it is to the gaming executives who make the decisions of whether to bring the game over or not. And trust me, those executives aren't going to base important decisions around a game that struggled to break 6 digit sales. They'll look at the one that sold half a million.
And even if you don't believe that, there's the facts. The SRPG rush clearly, clearly started in the PSX era, before Disgaea.
Arc the Lad, Fire Emblem, Vandal Hearts, Brigandine, Front Mission, Kartia, Hoshigami (argh)... uh, none of these have a chance of coming out if not for FFT, except Fire Emblem, which needed Smash Bros. Melee, though I dunno if Nintendo would have the guts to bring it over if not for FFT either. All predate Disgaea.
I don't recall Disgaea having that sort of effect on anything except other N1 games. Other SRPGs that have come over recently...
-Fire Emblem series coasts on the fact that FE itself has been a success, obviously. Same goes for any other sequels still appearing.
-Wild Arms XF came over because XSeed is quite happy bringing across that series and accepting the low but reliable niche sales.
-Similarly, Suikoden Tactics came over because Suikoden games proved financially viable. The very fact that the name was changed from Rhapsodia to "Suikoden Tactics" for North America is ample proof of the two influences the marketing boys were trying to sell the game with.
-Games like Rondo of Swords and Jeanne D'Arc... I assume draw largely from FFTA and Fire Emblem, two of the biggest GBA titles, which proved that portables and SRPGs are a good mix (I've seen casual gaming media comment on the influence of those creating the portable SRPG market). They certainly didn't need Disgaea PSP to light the way.
I'm really not seeing it at all.
