It's a question of verisimilitude, not realism: we are looking for experiences that we can believe in.

Firearms in games tend to be less real because they prioritize making you believe in the power fantasy of a gun: it looks and sounds fearsome, and enables the bearer to dispense death. Running and jumping, likewise: there's no need to explain in an empirical sense how or why Mario jumps extremely high - it's an aesthetic choice that highlights the thing the game is about.

We tend to get stuck on portrayals of physics, camera, and photorealistic rendering in games because in those instances, we have tools that are good at systematizing verisimilitude: the car can behave more like a real car by fastidiously emulating everything we know about real cars. Those simulations can be made comparable to ones used in industry.

But many aspects of games can't take that approach and have to be cartooned to some less grounded approximation: the way in which human figures move and talk, or how a national economy works, or the pacing of combat.

As makers of designed products, we're meeting players in the middle by making choices that cohere with the rest of the game's goals while staying believable to their expectations. There are lots of ways to achieve verisimilitude while destroying the overall structure of the game, and that's a classic newbie-designer pitfall: "do X but with more detail".