Recipe for a billionaire includes:
- (optional) being born wealthy
- Exploitation of others
- luck
Billionaires like to think they worked hard but in reality they exploited others and were lucky in some form or another. Exploitation comes from paying workers as little as possible and/or having such terrible work conditions to maximize efficiency to the point that who cares if someone dies working. Fighting unions and keeping costs down (including pay) means more profit. It also means you can charge less to force other competitors out of business unless they can do the same amount of exploiting to keep costs down.
Beyond that, there's just general business and economic concepts like operating at scale which luck or generational wealth can help shortcut there.
Being born wealthy can also just be wrapped into luck. But i separated it because it isn't strictly required, however unlikely, to become a billionaire. Exploitation and luck in some form is required every time.