[gruez]

>If I retire by early and through compounding interest amass a fortune that would allow my children to retire before they even enter the work force, is that ethical?

It's easy to argue it's unethical by invoking utilitarianism. Unfortunately that also means basically anyone with a white collar job in the first world are unethical, which I'm not sure most people would agree. Other than that I can't think of any convincing for why that's unethical.

[jpetso]

My take would be that actively working against both equal opportunity and equality is unethical. By giving your children a giant leg up, you're taking from all of the others.

Imho society should be liberal in letting people acquire and enjoy their wealth, and strictly limit the passing down of wealth to prevent dynasties and having someone's opportunities decided by their parents' means. This would solve a lot of compounding problems. However, people are generally pretty terrified of not being able to let one's own kids inherit the entire fortune and sharing it with other random kids too. We'll likely continue along those lines for a long time coming, whatever your stance on ethics doesn't stand a chance against family bonds and their voting power.