When and why did video games become "for children" in the US?

It wasn't always like this. In the early days, video games were for everyone. Games like Pong and Space Invaders could be enjoyed by players of any age. Pac-Man fever wasn't only an affliction of the young and old, everyone was susceptible. If anything, early arcade games were more likely to be played by adults, because you were more likely to find them in smoky bars than any place a child might hang out. They were a natural extension of the nickelodeons, love testers, pinball machines, and other coin-op amusements found in such places for most of the 20th century. Then something happened, and video games became a pastime that was widely understood to be "for children". There was some market segmentation: computer strategy games and RPGs could be for adults, because they were cerebral, like chess. Read some old issues of Computer Gaming World or its contemporaries and you'll find reviews dripping with derision for any game with an action component, dismissed as a simplistic game for…