This is absolutely the wrong advice. You should pay off your debts, buy a house, blow away your mortgage and then optimise for passive income. You won't become the richest out of everybody you meet, but you will be a free agent.
Obviously don't disagree that a young person will get something out of working in a
or
. But personal growth tapers out as you get more experienced and find it harder to be pushed.
And eventually the need to hit a goal becomes greater than the need to grow a muscle.