A) Maggie S was able to restore the previous revisions of the Spanish subtitles for the PSY - GANGNAM STYLE (강남스타일) M/V video when they too got deleted by a roll back that produced a "retired user"'s revision: see the last comments of A roll back destroys Spanish subs and messes up most other subs for PSY's Gangnam Style video .
The two cases are slightly different, in that the Spanish subs for Gangnam Style were done as timed text. But I hope the previous revisions of the Spanish and German subtitles of http://www.amara.org/en/videos/EWwRBDz7PqSK/info/the-collapse-of-the-american-dream-explained-in-animation/ can be restored as translations from "English, British" subs.
Update: sorry, I should have checked: the Spanish subtitles for the Gangnam Style video that got messed up were also translated subtitles, and Maggie S was able to restore both their revisions 0 and 1 as translated subtitles, editable in the translation widget. So what happened to the German and Spanish subs of "The Collapse of the American Dreams" seems to be exactly the same case.
(1) That ticket was http://support.universalsubtitles.org/support/tickets/4657 . But only people working for Amara can see it..