And at every step there has been aggressive active resistance to that by the audience. Even just recently, book publishers floated an idea a few years ago to put recommended age ratings on books aimed at the childhood and adolescent markets. Readers, authors, and all fans of literature exploded. They launched boycotts (and unlike gamers they're not lying when they say they'll boycott something), they got loud. Publishers quickly backed down. Gamers would never think of resisting age prohibition rankings. In the movie industry, we had the Hayes Code for awhile and movie fans opposed it unceasingly until it was eventually repealed.
And with games we face higher censorship than in any other medium. In movies, for instance, if the movie features animated characters rather than real people (as all videogames do), you can get away with essentially anything at all. Just look at the South Park creators and their movies. And you can get an unrated movie and pop it into your player and watch away. With videogame consoles the console makers have all declared they will never permit an unrated title to be licensed, nor will they ever permit any title given a rating that restricts it to an audience of 18+ gamers. And thanks to the DMCA section 1201, that edict of the publishers gives the ratings handed down by the ESRB the full force of federal law.
And you have to consider the 'Chilling Effect' as well. You can't even propose beginning a project in the gaming industry that has a significant risk of being black-balled with an AO rating. Most gamers look at M-rated games, which are equivalent to PG-13 blockbuster action movies at their most 'extreme', and think its equivalent to an R rated film. They would never think of standing up and saying 'content on a screen is not harmful. Ratings are restricting what we have access to in significant ways and need to be stopped.'
We don't have ratings on books. When you go to a bookstore, there is a 'childrens section'. That is sufficient, and no more is needed. No prevention of kids from grabbing books intended for an older audience, no group of 'concerned parents' declaring the appropriate age range of readers, no ratings agency charging tens of thousands of dollars to grant a rating which is used to determine whether a reading device will permit it to operate. Gamers are downright scared of such a system for games, though. And for no legitimate reason.
When pablo escobar sees $800 from cocaine sales in the US he didn't see just "hey this works, lets try to make it work elsewhere" he sees "hey this cocaine shit is addictive, lets sell them more and kill anyone that gets in our way".
This is why we tend to make predatory things illegal, because they use their vice to corner the market and control the user.
> In other forms of media, the audience vehemently defends their chosen medium, combatting censorship, responding to exploitative practices with substantial actions to back up their complaints, fighting for the rights of the audience over those of the publishers, etc.
Eh, I don't really think you know too much about other mediums then. Television and Radio have had massive amounts of censorship in US history. Between the FCC and MPPC the government has been very hands on in those industries.
The reason it seems different in video games is sales are not restricted in the same manner. There were only a limited number of radio stations, television channels, or movie theaters in the past. With games, especially recently, digital distribution is effectively unlimited. You don't have to fight for the medium because there an unlimited number of games you can play or places you can find them. Why fight, you'll just die tired and have less time to play a different game.