Concentrated trades is how you get wealthy, spreading your bets is keeping your wealth.
But this is a once in a liftime chance. I can‘t believe people on a tech forum are so blind to the fact that we are in control for the first time. Hedge funds dump money into a system which they can‘t read or understand. It was the opposite for hundreds of years. The average Joe had to trust the financial world. Now YOU can read the code the money runs upon, all in the open.
So yes, show me how you did perform with your FIAT money in an age of money printing.
Your words were true up until 2008, everything after that: Throw away your old school investment books, they don‘t work anymore.