Well, maybe not the cereal itself. After the marbit was invented, the evolution of the product seems to have stopped. It's now merely a formula of recombining the 4 basic grains (flaked, puffed or biscuit-style) with some combination of artificial flavors, colors and shapes (marbits optional).
But the pinnacle of confluence of product and marketing was definitely the '60s (and arguably the early '70s -- any decade that produced both Frankenberry and Count Chockula and Freakies must have done something right). In the 1960s, animation for television hit like a blockbuster, and nothing made for a more natural symbiosis than early-morning TV cartoons and a sugary prepackaged breakfast food that kids could make for themselves without having to wake up Mom and Dad. All that was needed were spokesmen, and Hanna-Barbera and Jay Ward Studios blazed the trail that others followed. First Huckleberry Hound (WHY did this character never have his own cereal?? We had to wait for Boo Berry) and Yogi Bear hawking Kellogg's cereals, then Rocky & Bullwinkle humping for Cheerios. Leading to the creation of The Linus the Lionhearted Show, an entire half-hour program starring cartoon characters specifically created to serve as mascots for Post kids' cereals. When Jay Ward decided to get out of the competitive arena of network TV cartoons, Quaker Oats Company kept him employed creating original commercial cartoon characters Cap'n Crunch, Quisp, Quake, Quangeroo, and King Vitaman. With all of this, it's amazing to me that the universally-recognized stables of cartoon studios Disney and Warner Bros, with the likes of Mickey Mouse, Donald Duck & Goofy, and Bugs Bunny & Daffy Duck never wound up hawking cereal on TV.
The synergistic cycle of character icon, cereal, cartoon animation, cereal, packaging design, cereal, promotional prize, cereal, was never more perfect than it was in the 1960s. Then parents and congress got into the act, and we found out that cartoons were too violent, cartoon characters were forbidden from endorsing products in advertising during their own shows, and before long the word 'sugar' became a dirty little secret and was removed from product names and box logos (although it didn't move anywhere down the list on ingredients labels on the packages).
The 1960s was a simpler time. With myriad cable channels today, there really is no more "Saturday morning TV" in the sense that we knew it when the triumvirate of CBS, NBC, and ABC ruled all. In the last 20 years or so, the resurgence of a once-moribund television animation industry has also coincided with an enormous profusion of TV and movie character tie-in cereals. Every year brings new kids' cereals that bloom briefly like cherry blossoms for a month or so, only to fade like a passing fad.
Thank you, Scott Bruce, for letting us relive the memories.