DC has a bit of an advantage to the fact that people know their core characters: Batman, Superman, Wonder Woman, The Flash and to a lesser extent Green Lantern, Aquaman. The only real obscure one for most would be Martian Manhunter.
Before 2008 the large majority of the general public had no clue who Iron Man, Thor, Black Widow and Hawkeye were. Iron Man was a B list/C list consideration even from Marvel's own mouth before then. Before 2008 the only Marvel heroes that were readily known were Spider-Man, The Hulk, Wolverine maybe Captain America.
Marvel had to set a background whereas DC doesn't exactly have to because their characters are easily within the mindset of the Pop Culture. It isn't a lost cause because DC doesn't have to follow Marvel's path but they have a very high standard they'll have to meet.