I think it's fine to live at home as long as the person and their parents are happy, but everyone who does, should be grateful. Often, people who live at home say they were unemployed or didn't have a lot of money so had to, but even that is a privilege- my family was so poor and lived in the middle of nowhere. When I left for uni, there was literally no room for me to come back. We'd been cramped 2 kids to a room, all big, tall people, so there wasn't even a bed for me. I slept on the sofa in the uni holidays, and I even paid rent because I had a holiday job. But that's not sustainable for someone in their 20s with a full-time job. But also, some people will say they live at home so they can save for a deposit and not "waste" money on rent, and that is also a privilege. Fine if your parents are ok with it, but it's a privilege nonetheless. My mum couldn't support the kids who were still kids, let alone an adult as well. Some people, like me, didn't have any option but to go live in a share house, paying through the roof for rent, and living on beans and rice and never doing anything, because you had to just work and live and get on. Living at home is not just for poor people and it's not just for rich people so it should not be seen as a marker of success or not.
Did anyone ever see that show "how to live mortgage free"? They fell into three camps. 1. people who had bought in the 80s, had house prices rocket, made a killing, sold their house and bought something for the money they made. 2. people who lived at home for 5 years never paying a penny. 3. people who got an inheritance/payout/divorce settlement.