There is no easy answer to this question. However, lessons have been learnt. I believe that one key way of preventing the recurrence of Ponzi schemes is through financial literacy programmes.
The question is how the economies of Europe and the other advanced countries can revive and start growing again, when they are still suffering from high debt levels, extreme hoarding of liquidity, and an extraordinary degree of risk aversion. How do we get out of the problems we are in?