There are a few different things pushing this in my opinion as a 24 year old from Ireland.
Rent prices being so high especially in cities means younger people are more willing to live at home and earn less. Why bother moving into the city and having all your income hoovered up in rent costs. Many smart young people here on the forum are using this saved money to improve their lives and start businesses but the majority of people I know that live at home use this money for parties, drugs, trips abroad, fashion or social media flexing items.
Others are living at home with low COL expenses, making 1-2k monthly from a 'hustle' like personal training or an online business/freelancing then promoting themselves on social media and living a cool lifestyle traveling etc.. but they'll never own a home or save enough to progress.
Third category I have noticed are people who's wages wouldn't compare to anything mommy or daddy could give them. Earn a little bit of money from a hobby/hustle to keep them going but ultimately it's being topped up by the parents. In many cases this might not be a completely one sided relationship as the kids might be expected to work in a family business or take it over in time. Many type of young people in this scenario are pursuing arts/music/acting type of careers but they have the blue collar type businesses of their parents to fall back on (farming, industrial, retail, services, construction etc)
The final category are the stimmy check/crypto/nft homerunners. I know a good few people who made 50-100k during the bull run on these type of asset classes (2019-2021). They are living lavish now and going on lots of trips/flexing but the cash will run out eventually by 2023-2025.
Edit: Also cheap money is making everything accessible now. You can borrow lots of money to live nicely off now and delay having to do anything major with your life. Will be interesting to see what happens to these type people when interest rates rise. I'm talking about the HELOC people who release equity from their homes to pay for them or their kids lifestyles. Also, student loans - vacation loans, car loans, personal loans.