This is a fantastic idea in theory!
I say in theory because, as you can imagine, there are so many factors that contribute to this idea being logical. As much as I would absolutely love to be driving around with AI traffic, I'm sure there would be many challenges the developers would face in even attempting to offer support for it. I'm sure if there comes a time that this idea does come to fruition, it will need to be adapted for multiplayer use and all of the trolls that come with that.
I also remember seeing a teaser video from TruckersMP about adding private servers for players and their friends to drive with AI traffic, as opposed to implementing this feature with as many players as swarm the ETS2 Simulation 1 server on a weekend.