this is the ego of the gambler who thinks he is not a gambling addict but it is different from the reality because they are indirectly included in it 
But on the other hand, there are experiences that must be used as a reference so that terrible things don't happen again. But as you said problem gamblers are not aware and will always get to the worse.
It could be changed but without the gambling addict's willingness to change through rehab. I have seen and know in person that even if you tell him/her that she is a gambling addict but their response is that he/she is not a gambling addict and they didn't gamble everyday but the truth is they alway gamble everyday. Mostly in my country they play card game.But on the other hand, there are experiences that must be used as a reference so that terrible things don't happen again. But as you said problem gamblers are not aware and will always get to the worse.
Many people will get into a denial stage of urging too much gambling because they are already addicted to play with. It is more ideal if someone on their family or friends guide them to prevent too much addiction in gambling. Sometimes it does not help to the mental stability of a person when get too much addiction they make a decision which is not give a good outcome. This is the reason why we must need to have a self awareness when we play gambling.