Largely, I grew up after the H-B heyday, but of the so-called animation renaissance spurred on by the critical and commercial success of Who Framed Roger Rabbit, which helped revive the Disney Feature Animation unit, and encouraged Steven Spielberg and Warner Bros. into producing animation for television. (Remember when Tiny Toon Adventures got a primetime special on CBS for its premiere?) Disney got in to the act by expanding their daytime offerings into a two-hour block, calling it The Disney Afternoon. With Fox entering the scene, you had a small but active environment for animation, which of course helped spur the creation of Cartoon Network.(Ironically, a 24-hour animation network would eventually kill off afternoon cartoons on network TV, and drain the remaining audience for SatAm cartoons.)
Now, it may be giving too much credit to Joe Barbera and Bill Hanna to say he kept animation alive from the 60s-80s through their Saturday morning works (and the Flintstones in primetime), but if nothing else, they kept a lot of their colleagues in work, and inspired lots of kids at home, through those cartoons, as well as through those Tom and Jerry shorts from the 1940s onward. J.B. also was one of the helpful bridges to the history of the medium. He will be greatly missed in the animation community. I'm glad to see he will be missed by Cartoon Network, too.