Warner Brothers Studios was incorporated in 1923 by the four Warner brothers (uh-huh), already veterans of movie sales and distributions. The brothers realized that the real money in movies was in production, so they purchased a lot on Sunset Boulevard and went to compete with the big boys of Paramount and Universal Studios. Warner Brothers was around in the Golden Age of film, and it's still around today. The company has more staying power than Rob Lowe. (That guy is still relevant? Amazing.)
The reason it's still around is that it built its reputation on movies like Casablanca. After getting its feet wet (okay, soaked) with hundreds of silent films, it brought the magic of sound to the movies and counts among its early successes in the sound era such classics as The Jazz Singer (the first "talkie"), Broadway Melody, The Public Enemy, Mutiny on the Bounty, Gone with the Wind, and The Wizard of Oz. And those were all pre-Casablanca. Not a shabby résumé.
Warner Brothers was all about big budget pictures with substance. In recent years they may have released such masterpieces as We're the Millers and Horrible Bosses (sorry, Jason Sudeikis, we still love you), but the majority of their releases are emotional or thought-provoking pieces (Cool Hand Luke, Who's Afraid of Virginia Woolf, Mystic River) and cutting-edge stories filmed on a grand scale, like Inception, American Sniper, and Gravity. Not to mention blockbuster franchises like the Dark Knight, Harry Potter and Twilight films.
They've done okay. You'd better believe they're still on the lookout for the next Casablanca though…