When American kids turn 18, they are directly "weaned" and become independent. I have seen several myself, and it’s truly moving...

A high school student just turned 18, attending classes while working part-time at a restaurant, voluntarily paying his parents $100 a month in rent. I asked him if he thought his parents were too harsh. He looked relaxed and said, "That's normal. If you live at home, you should pay." No resentment at all.
There’s also a slightly older one who has been working full-time at a restaurant, and he directly rented a small room and moved out of his parents’ apartment. He’s saving money and planning to attend Community College in the future, with a clear goal, living like a little adult.
In contrast, many of our Chinese families... Once, I picked up a middle-aged American man in his fifties or sixties from the airport, chatting casually along the way. He asked about my children, and I casually said, "My son is over 18 now, still living with me, not paying a penny in rent, and I don’t even let him do chores." The man’s face immediately changed, he was silent for two seconds, then only managed one word: "Ridiculous!" At that moment, I felt completely embarrassed.