Atleast is true for this industry.
By the way.. the money "industry" have this %
There are only few Mac donals who have tons of money and tons of burguer restaurants that dont have that sales...
there are few Zara clothes who have tons of money and lots of makets with no name which sales are "nothing".
So maybe is not in every single industry... but is also true is not only in creative industry....
The only true fact is there is "almost" 95% non successfull people / market / industry and 5% very successfull / rich people / market / industry.
By the way im in the Hobbyists sector