In the late 80's and early 90's real time was a feature of simulations. It's what made them simulations. And as dull as flying a WWII airplane out and back sounds...Microprose's Silent Service let you operate a submarine across the Pacific in real time.

Of course, you could also speed time up if you wanted. But a "base frequency" of real time means the game play is not centered around "story mode." In simulation it means the player experiences the simulation at the same pace real world events might unfold.

The quintessential game of the period might be Microsoft's Flight Simulator. Which is only a game in the sense that the consequences of a bad day don't cost very much.