I guess they just prefer spending their millions of dollars and unlimited time with their families instead.
My dad retired at 57 in the 90's.
He doesn't know how the internet works, can't search for things, and still uses paper for bills and banking. He doesn't know how to use the iPad I bought him (outside of clicking the links I made into icons). He can't type.
In the last 25 years he lost the ability to communicate in english. I have to make all calls to government agencies for him, i have to buy his tickets for him, make his appointments for him, and I live on the other side of the country.
His brain barely works. Has the memory of a goldfish and has been brutally depessed for the last 20 like he has no meaning.
I don't think a 35 year old should retire. Your life needs to have meaning or it will get boring and purposeless really quickly.
My dad's at the age where most of his friend and family are dead. There is nobody who can relate to him, or he relates to.