After September 8, I knew that this was not the case.
Although Wendy and Marvin were nobody's favorites, they were of their time. Scooby-Doo, Funky Phantom, Speed Buggy, Captain Caveman, etc ALL had young adult protagonist, for example. After they left we were given super-hero sidekicks who were, at the very least, more logical than two kids and a dog. The first season of SF begat The Wonder Twins, The Legion of Doom, Global Guardians, and, arguably, The Super Powers action figure collection. Each of those promulgated in-numerous after effects on their own. If The Super Friends had not been a success, do you really think we would have had all of the super-hero goodness we have now? So in a sense, we can credit The Super Friends with the flame that eventually became our entire Super Hero Pop Cultural Phenomenon. And just like the comic book JLA has been given credit for helping to create the Marvel Universe (Marvel's publisher saw the success of the JLA and told Stan Lee to create something similar; he came up with The Fantastic Four), The Super Friends can be credited with creating the environment where Spider-Man and His Amazing Friends, The Fantastic Four, The Hulk, and all the other Marvel projects from the Seventies onward could find success.