Rather than choosing to take their bestsellers and stick them on a team together (like DC did with the Justice League), Marvel chose to revitalize some of their less popular characters by teaming them up. ... DC, on the other hand, had all their characters. Especially the best ones. Superman, Wonder Woman, Batman.
what I think is true: DC Comics and its characters are often known for being dark, serious, and brooding; the most famous example of this is Batman. While, Marvel is known to be less serious, lighter and focuses more on entertainment.