And it's thanks to Flash that Atlas became Marvel, and started churning out new Super Heroes. And while Stan Lee unabashedly took ideas from DC, he did provide a more mature look for comics at the time, while DC was embracing the "Silver Age" weirdness. It's funny to think how the 60s nearly killed the Batman though, and he was pretty much saved by Adam West, while his book floundered.
And while Supes, Bats, and Wondy kept their title features, DC did keep Detective and Action running, and while we tend to think of them as just a Bat/Supes book by another name, they were anthology books, and characters like Green Arrow, and Aquaman rode out the Golden Age into the Silver in Action.
Flash is in part one of the most important characters for DC, he is a herald of change, and He brings with him great change, the Silver Age, Event Comics, Flashpoint, Rebirth