I don't think cartoons were really targeting kids until the 70s. Flintstones and Jetsons were prime time offerings. Rocky and Bullwinkle was heavily steeped in global politics. A lot of the Loony Toons stuff was a parody of adult situations, that while presented goofily enough to entertain kids, had much more message for the grown-ups. If you watch these as an adult, you glean a lot more than you did as a kid.
I'm not enough of an animation aficionado to know when things changed exactly, but in my memory it was about the time that Clutch Cargo and Speed Racer hit the scene. The cut-rate animation and plots would not have held adults interest for long. It probably coincided with the time in social history when McDonalds felt the need to add toys to their meals. Animation tended to turn into a children's product marketing ploy after that (at least in my memory). It wasn't until the Simpsons came along in the late 80s that (non-porn) adult targeted animation came back into fashion.
If you wanna eat candy from those, have at it. Not me.
