I did not read all 7 pages of replies so my apologies

I started cluing DS19 into my expectations of when he would leave home when he first started high school. My "rule" was/is you can stay home the summer of graduating from high school until that Labor Day Weekend. At that point, you have options ~ 1) college and you can either commute and live at home or come home on holidays and for the summer (but must go full time either way); 2) military, or 3) get your own apartment. He did ask whether he could stay home if he worked full-time and my answer was No. I did tell him, however, that if his intention was to start building a horticulture business and was going to put all his time and effort into building that business I might reconsider. He is now in the Air Force and very, very happy
My daughter will bear the same expectations. I think our children need to show motivation to start their own lives once they complete high school. I see far too many kids living at home, working 30 hours/week, driving new cars, having all the best electronics, and Mom/Dad both working 40+ hours, driving a junk, and struggling to keep their heads above water because they are essentially still providing for their grown children. Not in my house.
Of course, there are many variables to the situation but this is my answer for a child who is capable of higher education and/or hard work and doesn't have other issues to consider. Lack of motivation isn't an option.