There are games such as Tie Fighter and Half Life where you make your way through a story going from one event to another as you succeed at each challenge but once you have reached the end of the story there is nothing more to do and if you start again you will go through the same steps as before.....
Can you clarify? You're saying that gameplay is not essential to the program and is fully optional; mostly left to the imagination?
With Elite you can go almost anywhere in the galaxy and while your activities are more limited than that you can do as much or as little of each one as you wish and if you start over you will not get an exact repeat of what has gone before.
So yes things like missions, power play, BGS manipulation, ranking up with the navies are all optional and you can imagine your own reasons for what’s happening and why you are doing what you are doing.