In many other cultures in the world it is totally normal, and people don't seem to suffer for it.
When I tried living on my own for the first time, the only difference was I had more privacy, but paid more money. I didn't change, or 'grow' as a person. It wasn't difficult or challenging. I already paid rent living at home, now I was paying more rent. Big whoop. I feel the importance and impact of moving out is grossly over-exaggerated.
I'm with you. There's a bit of arrogance in believing the only way to grow into an adult is to spend your 20's away from home. Millions of people, for thousands of years, all over the world have managed to live full lives in multi-generational households.
And I've not seen anyone in this thread articulate specifically what life skills are learned and what growth happens on their own. Do most American parents feed and shelter their kids from age 0-18, teach them nothing about life, and then let them figure things out themselves? Cooking, cleaning, budgeting, paying taxes, navigating leases, etc all seem trivial to learn IME. And they ought to be learned well before 18.
There wasn't any great rationalization on my part, or fear of stepping out of my comfort zone. There was math, and it was this:
Age 22: $20,000 saved @ 5% real return compounding 45 years = $179,700.16 at Age 67
Age 23: $20,000 saved @ 5% real return compounding 44 years = $171,143.01 at Age 67
Age 24: $20,000 saved @ 5% real return compounding 43 years = $162,993.34 at Age 67
Age 25: $20,000 saved @ 5% real return compounding 42 years = $155,231.75 at Age 67
Age 26: $20,000 saved @ 5% real return compounding 41 years = $147,839.76 at Age 67
Total: $816,908.01
I did it, my siblings did it, nearly all my friends did it. Done saving for retirement, that's real independence in my book. Obviously I'll keep saving at least up to my employer match, but man is it a great relief.