Hasn't the same thing happened in television, movies, and music as well? Compare the music of today to the music that was popular 60 years ago and I'm sure you'll see a huge difference in the references to sex and violence. Videogames are like everything else, a reflection of our current society.
Also videogames are for everyone so why do some people show them a complete lack of respect and want all of them to be censored to be acceptable to pre-teens, young teens, and religion? What would people here think of people who wanted television, movies, and music censored the same way?