Greed works. Fear of missing out pulls them in. They got some easy money, changed their thoughts about money into thinking it should be easy, that's it's been easy all along and they didn't know it until now, so they plunge it all in, thinking this is how it will be from now on, trying to "make up" for lost time when they didn't have it.
They changed how they thought about money, instead of cherishing it and protecting it, they reframe what money is to them. 50% of all big lottery winners are back to their original financial status, or worse, within 5 years, for the same reason.