I think PP have nailed it where the adult male has moved back after a divorce and if they've never moved out they are treated like royalty so never feel the need.
I moved out at 18 into university halls and went home for the next four Christmasses and Summers until I found a graduate job and flat. Getting away from my parents was my only goal and I became a home owner at 25. They didn't even help then. I scraped my things into binliners, packed my car and off I went. Years later, after my divorce I had to live in an air b&b for 3 months until my new house completed. I asked my mother if I could perhaps use her washing machine to wash my and the DC clothes. She refused.
My brother meanwhile, never left home, dropped out of university, worked and kept all his money. They fed him, bought him clothes and shoes, kept him warm, helped him with his car. He repaid them by becoming a violent alcoholic and drug addict who used their car to deliver drugs, pushed my mother down the stairs and brought escort type women to the house. He still lives with my elderly parents, sans job, car or.driving licence. He does however have a criminal record, benefits and a voluntary job in the charity shop. According to my mother he is doing very well and she couldn't possibly kick him out.
To add, neither of us were taught life skills. We were not allowed the kitchen and had to eat the meal provided and nothing else. Neither were we allowed to use the washing machine. I know deodorant was bought for my brother when he became a teen but I had none until my student loan came through.
It's so sad. My brother has wasted his precious life, helped by my mother who wasn't willing to let him go.