One of the first thing you are taught when learning programming or game design is that complexity is the enemy. Its the price you pay to add the stuff you need to your project. I have found this holds true for any large project, including novels.
Every character you add, every new technology, everything makes things more complex. This is not to say you should not add more characters or add more technology, it means you should do so only with good reason.
To be clear, “It makes the setting feel more real,” is a perfectly good reason to add something. But you need to have SOMETHING to tell you to put it in, everything you add could bring new problems.
Think about the best movie you have seen, were there any wasted scenes? In most really good movies most scenes do several things at once and everything they do is necessary.