What makes the Sims franchise so different from more traditional games, in my opinion, is the fact it has universal appeal. As humans we are incurably nosy about our fellow humans regardless of our age or gender. What better then than a game which allows us to set up scenarios with miniature humans and then watch all their activity. Long may it continue.
I think this life simulation game has helped break down the barriers of gaming being the exclusive territory of the young. I think it works as an introduction to gaming for both young and old. I had never really considered gaming until my forties and it was the Sims that got me started. I will also say it was my nephew who introduced me to it and while I have been happy to go on playing dolls house he has moved on to games which appeal to him more.
I will add that it has also made me learn a great deal more about computers. As the OP said home computers were very rare when I was young and it was not until my twenties that I started using one for work. Now I have a very good idea of what my next computer should be capable of in order to run TS3 properly. All other considered uses for the computer are secondary to this :)
I never thought my gaming life would dictate so much. This brings me to my final point that the Sims, like most games, is addictive. Maybe this is because you, the player are in control, or the fact the game is open ended. In my case I suspect it has more to do with the fact that I am not only ancient but incurably nosy.
