why is it that more than more 70% of lottery winners end up going bankrupt eventually, after just a couple of years of winning?

Lets say someone wins the lottery for 3 million after taxes... why is it that they still end up going bankrupt?
My theory behind all this is that, only the poor and middle class people win the lottery. (that would be a fact, since rich people don't gamble, they only take calculated risks..)
So a poor man wins the lottery. now the reason he's poor is not because his earned income is to low but because he doesn't know any positive things to do with the income he makes. (I think we can all agree on that). Instead of buying assets with his earned income he would have alot of liabilities and useless expensives.

Now he wins lottery for 3 million he still doesn't know the game of money, so he would now be a RICH man, with a POOR mans mentality. Now if this is the case he would eventaully lead back to his old ways. Buy buying more liabilities and accuring no assets
Additional Details
this will end up leading him into the same problems he had when he was poor. So now all that changes is the amount of money he was but the RATIO stays the same. So if what I am saying is true.. all that would happen is he would now be in debt by the tens of thousands instead of a couple of thousands and then would be force to declare bankruptcy.