Thats not really true, its a misconception people carry from the 60s when they really shaked the industry, but since then both companies have their fair share of pusging boundaries.
In fact the last "big" shake up in the comic world was led by DC in the 80swith Swamp Thing (and everithing Moore did), TDKR, Crisis on Infinite earths, etc. Swamp Thing and Animal pretty much created their own imprint (Vertigo) .
Even things like the Ultimates or what was called Nu Marvel in the early 2000's were the same concepts we have seen of wide screen action and decompresion of the genre done by books like the authority, wildcats vol 2 (published by wildstorm wich were DC bookS). The ultimate line in general is similar to the post crisis revamps characters got in their origins.