Also, why would Sony want to make a FF-killer? Final Fantasy is the second most popular JRPG (after Pokemon), and it sells more on Sony's platform, so it wouldn't make sense to compete with a series that already makes them money. And more importantly, a series that makes them money without any investment on their part.
Sony created Freedom Wars despite God Eater being exclusive to their platforms.
Sony created Bloodborne despite Souls selling best on their platforms.
Seems like everyone forgot about oreshika.
Which is highly intriguing given
what has been said about that game.
Ah shit you're right, for some reason I was seeing 2014 as the article date. Well my hopes of a new console RPG by Level 5 has just gone to the shitter

.
The conversation was about Sony partnering up with Level-5. That's pretty unlikely now as Level-5's IPs are bigger than anything Sony has in Japan.
But Level-5 is free to self-publish their own creations on PlayStation platforms. Outside of Wonder Flick, which has gone MIA on consoles, it isn't looking great, though. Level-5 is deadset on the child market and that's one not really suited to PlayStation in JP.
Grandia is owned by Game Arts.
Sadly, Takeshi Miyaji, the creator of Lunar 1/2, Grandia 1/2 died in 2011:
http://www.destructoid.com/grandia-creator-takeshi-miyaji-dies-aged-45-207622.phtml
Sooooo, I wouldn't count on Lunar or Grandia ever making a return.
I'm feeling confident in saying Matrix Software owns Alundra, though I don't have a definitive source on that.
Edit: Originally I said Sony didn't touch Alundra 2 in terms of Publishing. Double checking shows Sony did publish it in Japan. So maybe they have partial ownership? I don't know
I'm not too sure about Rogue Galaxy. Wikipedia says it was a joint Level-5/SCEJ project and it was published by Sony. So it's likely Sony does own it.
Yeah, everything went to crap in Dark Cloud 2.
edit: THIS IS SARCASM.
My comment wasn't a dig at the game's quality. It was entirely sales based:
Dark Cloud 2 sold worse than the first despite launching on PS2 in its prime. SCE and Level-5 probably thought they could do better with a new IP, hence Rogue Galaxy, but it did worse. Then WKC came out ... and did worse than every prior console game.
Declining sales is a fault of every SCE RPG mentioned in the OP (Japanese data via Famitsu):
PS1 : Wild Arms ( SCE ) { 1996-12-20 } - 116,393 / 415,138
PS1 : Wild Arms 2 ( SCE ) { 1999-09-02 } - 164,082 / 280,037
PS2 : Wild Arms 3 ( SCE ) { 2002-03-14 } - 156,997 / 273,318
PS2 : Wild Arms Alter Code: F ( SCE ) { 2003-11-27 } - 102,543 / 167,254
PS2 : Wild Arms 4 ( SCE ) { 2005-03-24 } - 131,728 / 186,221
PS2 : Wild Arms 5 ( SCE ) { 2006-12-14 } - 68,789 / 117,975
PSP : Wild Arms XF ( SCE ) { 2007-08-09 } - 28,508 / 52,090
PS1 : Legend of Legaia ( SCE ) { 1998-10-29 } - 139,844 / 314,493
PS2 : Legaia 2: Duel Saga ( SCE ) { 2001-11-29 } - 40,302 / 72,413
Note: Legaia sales only account for two months for the original and a single month for the sequel.
PS1 : Arc the Lad [Playstation the Best] ( SCE ) { 1996-07-12 } - 20,770 / 497,253
PS1 : Arc the Lad II ( SCE ) { 1996-11-01 } - 316,225 / 816,873
PS1 : Arc the Lad: Monster Game with Casino Game ( SCE ) { 1997-07-31 } - 27,579 / 27,579
PS1 : Arc the Lad III ( SCE ) { 1999-10-28 } - 209,088 / 379,040
BWS : Arc the Lad ( Bandai ) { 2002-07-04 } - 11,458 / 28,157
PS2 : Arc the Lad: Twilight of the Spirits ( SCE ) { 2003-03-20 } - 80,627 / 185,862
PS2 : Arc the Lad: End of Darkness ( SCE ) { 2004-11-03 } - 28,981 / 48,667
Note: Don't have sales for the original Arc release.
It looks like DC2 sold more than the first in Japan, but I only have two weeks of sales data for the first.
You have a pretty clear picture of decline in those series. Budgets only grew with each platform generation but the sales did not.