I see nothing wrong with staying with parents indefinitely. The reason to move out would be for 'personal space and development' ... but having a strong sense of family and bond is a good thing.
When my daughter grows up, there will be no 'push' for her to move out. She could stay with us her whole life if she chooses; though unless the guy or girl she falls in love with is tolerable, I might not find sticking to that conviction quite as easy
I think some cultures are rushing kids out on their own far too early. 18 is no where near as mature as an 18 thinks they are. Mid to late 20s is when I feel people, besides exceptions, become closer to the level of critical thinking needed to survive alone. The time from 18 to when they leave should be the start of the real life lessons from the parents. They should be focused on furthering education and learning the value of a dollar and paying bills.
I'll probably give an option; work and pay some bills, or volunteer time somewhere, like animal shelters. I'd prefer she further her intelligence and volunteer her time than work and pay bills until about 22ish (about the time to get a 4 year degree ). At that point, strong push for getting an income and supporting the household in various ways would be a goal; unless they are working towards an 8-10 year masters/doctorate (ex: vetinary/human medicine).
The way I see it, give them love and support. Teach them what they need to survive. Don't push them away for the sake of it. Hell, when I get old and frail, I'd prefer they have a strong bond with me, and rather me stay with them and help out around their house, than throw me in an old folk's home to rot because I kicked them out lol
Ofc, nothing goes as planned, and she could move out at 18; and I'd be fine with that as well, though discourage it somewhat.
Why do people feel if 18 isn't old enough to drink responsibly, it is old enough to die for a country or take on the huge responsibility of living alone and acquiring debt and starting the life long responsibility of large monthly bills for the rest of their life?
If I can provide, I will. I brought her into the world, she is my responsibility, and I'm proud to do my loving job as a father. It isn't a rush to 18 to get her out, if all I wanted was for her to leave, I would have had second thoughts about having her in the first place; which I didn't.