No, it's really not. Like really, really not "harder and more complex" for the GM to run a game like that. It's infinitely easier. I do that kind of minimalistic gaming regularly. It's far more of a chore to worry about the complexity of the system as written than to make a call and/or declare a DC and push forward. If the GM and players know the world well, you can get a game up and running inside of five minutes (including character creation). If you're worrying about game books and mechanics, it'll take you longer than that just to talk about which game system to play.
It is simplifying because instead of wondering what the rule book says about physics and how the game differs from physics, you can start with everyone's rough idea of cause and effect and just get on with it. It's only things that change physics that take a moment longer to suss out. If you can't agree, pick some dice and make an opposed roll. Whoever wins is right and that's how it plays out. And you move on. Remembering all the ways the game mechanics break physics is a lot more of a mental load.
ETA: If you roleplay your character as person living in a real-to-them world, the game mechanics don't matter. So you don't need to worry about them. Not only do you not need to know them, you mostly don't need to have any. If knowing the game mechanics will change the decisions you make for your character, that's metagaming, and playing to the rules of the game rather than playing a person living in a real-to-them world.
I think it can be a barrier to play a character living in a real-to-them world if there's a lot of ambiguity concerning how that world works.
I agree with that approach to playing a character. Though, personally, I find that having some general understanding of how the world works helps in that endeavor more-so than it hurts.
A lot of the issues I have when trying to teach D&D to newer players is that how D&D says something works sometimes greatly differs from how they would imagine or intuit that a situation would play out.