Yes, it wasn’t a bad ending, just an unsatisfying ending for those who are hoping for a “Hollywood ending”.
Chigurh foreshadows the ending constantly throughout the movie with his coin-flipping monologues and dialogues to both Brolin and Harrelson’s characters so it isn’t like the audience can claim they weren’t being warned. Even Brolin’s wife and mother-in-law foreshadow the unhappy ending that is coming. Audiences just weren’t paying attention or didn’t want to believe it.
Much of Cormac McCarthy’s works are this way- Dark, Violent, Foreboding with no happy ending and usually no resolution.