I don't think they forgot the lessons. Its just that the allure of quick money is just too great for many people. I think this might be why a lot of people get addicted to gambling, for instance.
In this case, I think most people are aware its a bubble/ponzi scheme and are trying to "beat it" by making the most profit and getting out ASAP before the bust.
In this case, I think most people are aware its a bubble/ponzi scheme and are trying to "beat it" by making the most profit and getting out ASAP before the bust.