I don't think you're doing anything wrong, but maybe one of the reasons I don't play like you do is because I am more interested in the next generation than the original. I don't make backstories for my CAS sims, I concentrate on creating what will be the backstories for their children. This is why Sims 2 and 4 are way more addictive to me than SIms 1 was, because raising the next generation and seeing what stories I can create for them is what hooks me.
But if you werent supposed to start over as often as you feel like, they wouldn't have made it possible to make so many new saves. If creating the sims and setting them up is fun for you, there's no harm in doing the fun part over and over and ignoring the rest.
