The simulation isn't the reason for that. That's just the design of the game. Plenty of people enjoy the Truck Simulator games. Elite is basically the same thing, but for space. Also, I wouldn't call it a "simulation" of our galaxy, but a simulacrom or representation. It's not changing. The groups expanding and building in that, the economy, and those systems are simulations, and they actually provide content for the game, regardless of if it's enjoyable in your opinion.

Simulations that create content are when we should create simulations. Simulations that consume resources and don't enhance the game should be avoided.