You're mixing things up. Parental income can be seen as the result of parental traits that (if passed to the offspring) will help them in life - intelligence &

You're mixing things up. Parental income can be seen as the result of parental traits that (if passed to the offspring) will help them in life - intelligence & industry. Ie the parents are rich because they are smart and work hard. Those traits are passed to the children - who then follow suit.