I came across this because I was looking for news on the collab album. I didn't know if there was any more info such as a name or release date/label deal or whatever.
As far as Def Jux ending, El-P's addiction, and Aesop lyrics- Aesop's lyrics can be vague, as you know. He doesn't comment about El-P or Def Jux, and after tweeting each other about BBQ right before the label collapse I don't think they've interacted or mentioned each other publicly in 3 years. Aesop was by far the biggest act on the label, and his success probably subsidized most of the other releases, especially in the last 5 years. If someone wasn't getting paid I imagine (speculation) he would have been one of the label's biggest creditors. I don't know if Zero Dark Thirty is about El-P, but we DO know that he previously had a song about El-P saving his life, and that El was very supportive of his depression and inability to tour ( which can't help the label when your biggest artist begs off the first label tour and goes MIA during your formative years). We also know that El-P has admitted to drug issues and he has written about them in his slightly-less vague than Aesop lyrics.
I don't know these people or their biz operations, but at the time the number one and really only rumor floated blamed Cage's flop. That was probably overblown but all the blame in the rumor mill back in late 2009/early 2010 was centered on marketing investment on Cage's project. Maybe El's drug use caused him to be delusional to the point of expecting Cage to become an MTV hit after MTV stopped playing music videos, and thought investing label funds into Cage hanging out with Shia Labeouf was going to pay off. I don't know. I do know they spent their last 2 years or so focusing on a Cage project that sold about 2000 copies when it was released and then went nowhere, and resulted in Cage riding around in a van playing tiny shows with Yak Ballz and then opening for Less Than Jake, and an overhyped and pointless video directed by Shia and starring the kid from Cougar Town.
I'm sure the collapse was a result of cumulative effects from too many flops and not enough hits. Just from a common-sense business perspective, you have a label that had almost all it's success from 2001-2003, lost 3 of it's biggest selling artists (RJ left hip-hop or so he said at the time, Murs went major, Can Ox left twice without doing anything) around the same time, had a major backlash around 2004-2005 and released a bunch of flops (PFAC, criminally overlooked SA Smash, Multiple Hangar 18 and Rob Sonic LPs that didn't sell), only released 1 album (Mo Mega) during a period of almost 2 years-which did not sell, all of the higher profile follow-ups sold less than the previous releases ( Labor Days>Bazooka>None, FanDam>ISWYD, I Phantom>Mo Mega, Deadringer>SWLS) with up to 4 year waits, the 2 flagship artists (Vordul/Can O, Aesop) had depression and touring apathy/issues, did the US release and tour for a Platinum UK rapper with awards and pop hits but no one cares in the US and that sold few concert tickets and fewer CDs in the US, released CDs from successful underground vets (Del, Gift of Gab/Lateef) that did not sell, put out a bunch of random releases for friends and associates that had no commercial appeal and caused identity issues ( look at the discography from 2006-2009 and compare to 2001-2004), ISWYD was too little too late and None Shall Pass couldn't make up for the previous 4 years and the next 2, emo Cage alienated all his fans from the fat drug days and sold less with his new style despite the investment chasing new fans. Anything they made from stuff like Cold Vein and Aesop's catalog was spent on advances for other artists that flopped, royalty dispute settlements and other lawsuits, promo for followup projects that stalled, getting artists on MTV when they replaced videos with using bumper music for The Hills, staff/operations. Releasing one project that sells over 50,000 in the last 6 years ( compared to the early days when everything including vinyl singles sold like that) isn't going to sustain all that plus the creative director's coke habit.