Have you ever played with new players? I've ran non-dnd with new players several times. Including systems like Call of Cthulhu. Objectively speaking Cthulhu (BRP) is pretty rules light and my players had no trouble learning it. They just said what they wanted to do and I told them what to roll. They start to find the freedom in the system and get more creative. And a similar situation happens when I run more complex systems. I honestly have no clue what you are worried about. Players can learn how to play these games, they aren't that hard.