Exactly, jb--I can still hear my parents saying, at the end of every episode of Leave It To Beaver, as the credits were rolling...
"See what happens when...
* you lie to your parents
* you fight with your friends
* you miss a day in school
* you try to show off to people
* you dare someone to do something
* you do something wrong and then don't admit it
* you are not careful with your bike, jacket, etc.
By keeping these characters 4 years apart in age, the producers were able to keep story lines age-specific to both elementary and high school years. Beaver was still worried about not finishing his book report for Miss Landers while Wally was dating an older girl who smoked, had a fake ID, and was going to bars to drink beer.
Despite the fact that the Cleavers ate in the dining room every night, and June waxed the kitchen floor while wearing a chiffon dress & pearls (never saw anything like that on 18th Avenue), some of the kids' dialogue was thought provoking--"You know, I don't think Dad would like it if we..." or "You're just being a wise guy, Eddie"--some of Wally & Beaver's comments to one another were a 1950s version of "just say no".
Face it, if kids are going to watch TV (or play video games or hang out online) hour after hour, then they are going to develop values that stem from what they are doing, so there had better be SOMETHING worthwhile present in their entertainment.