Thinking about this question properly, it actually hasn't. DC brand isn't the same as a connected DC Movie Universe. Original Superman films did well, not including 4 or supergirl, and the first 2 Batman from the late 80s 90s did well too, plus the modern Dark Knight Trilogy (not a fan of them myself). It's just modern Superman who has struggled and DC struggling to get the others off the ground. Throw a few good screen writers at it and a few new up and coming directors like Marvel have and you might get something good.
DC has always been better at making TV series anyway.
Hmm, pie.