Well yeah that's why Ponzi schemes suck. Why should it be acceptable to profit from a Ponzi scheme? It's not your money at that point, whether you realise it or not.

> What is an amateur supposed to do?

You have two options.

1. Don't be unlucky. [1]

2. Or, you can make sure your society has socialized old age pensions, and that it puts in the work necessary to keep them solvent, and its citizens taken care of once they are past their working years.

[1] The easiest way to not be unlucky is to buy into a boring, diversified index fund. Berkshire may be a fraud, but it's unlikely the entirety of the SP500 is.