Well, a number of examples from TV have already been given. Aside from sitcoms, there was Star Trek, of course, and Man From U.N.C.L.E. and Wild Wild West and Mission: Impossible, among others. In music, there was the Beatles, the Stones, The Who, Bob Dylan, and so on, ad infinitum. In comics, both Marvel and DC were in periods of maximum creativity, as were other publishers, including alternatives like Warren and various underground comix. I mean it was the 60s; just look at just about anything from the period. Culture and counterculture were feeding off each other with an incredible synergy.Oh, sure it was. Those are just two examples of creative shows that had short lifetimes. If you look over culture in general, as I said, including TV, movies, comics, music, everything was in an extremely creative phase. That's just the way it goes. Culture goes through ups and downs; it was in an up phase then and, as far as I can see, it's in a down phase now.
Well, what other examples do you have, then? I already explained how the Hollywood film industry was in a period of relative decline until the late 1960s. I haven't seen a lot of television examples, either. I can't claim to be an expert about music or art of the period -- I barely know much about those arenas at all -- but in terms of film and television I just don't see it. "Oh, sure it was" isn't going far towards convincing me.
You said, "But that doesn't mean it's not creative." I counterpointed.You'll have to show me where I claimed that being dark and gritty make a show creative.Being "dark & gritty" doesn't necessarily mean a show is bad-- Lost and Firefly are two great shows which used those elements (one of which, like The Monkees, was canceled prematurely)-- but it doesn't make a show creative; that sort of thing has been going on since the 80s, so it's a pretty tired trope at this point. Nevertheless, all you need is to use scumbags and psychos for your main characters and the show will be labeled as "edgy."

Bloody Hell, no. That's the most horrendous (and laziest) cliche of contemporary culture.It can be quite creative if it's used as a new and interesting twist on an existing property that wasn't originally dark and gritty.