What is a Simulation?

Why does a simulation have to be historically correct?
Can’t a simulation alter events that may or may not have happened?

I want a simulation with a dynamic campaign that I can select a moment in time that contains a historically correct simulated world, but over the course of the campaign events can alter the world around me.
Maybe technology is developed sooner or at a later time or not at all.

I am not talking about one sub winning the war, but maybe, just maybe my actions along with other simulated object actions can drastically alter the campaign.

I want a dynamic campaign that allows the interaction of other objects.
Cause and effect of my actions.
Maybe a friendly ship in distress that needs help, maybe I can come to the rescue and fend off the attacker or just report its position so that a nearby ship can help.
Maybe I can command a boat that is a member of a submarine group that can attack a convoy or enemy fleet with coordination.
Or maybe I get assigned to help protect a convoy or a friendly task force.

Silent Hunter IV has the potential to develop into this kind of simulation.
But there needs to be more development with the dynamic campaign.

I know there is still alot of work to be done for fixing issues but maybe in the future....

Just wondering what other subsimmers think about this?