That may have been true at one time, but I don't think that holds for the past few years.
Marvel comics have been getting a little better, DC has been consistently bad since New 52. DC maaaaaaay have better amalgamation comics, overall, but Marvel had the best ones period (Secret Wars and Infinity Gauntlet are still enjoyable today. DC stuff has a shelf life in enjoyability and relevancy to its own universe)
The DC cartoons have been mostly garbage recently (*with the exception of Harley Quinn which is just fantastic). Not saying Marvel has gotten better, they haven't, but DC no longer makes good stuff*
Marvel will probably outpace DC on the show front soon with the Disney+ series.
Honestly, I would say that what DC has more of than Marvel is cultural momentum. Unfortunately, when that's all you have, you tend to have the terrible recent Batman products (except for his crossovers with the Teenage Mutant Ninja Turtles, those are fantastic).