I quite understand why that person did that, it's why I don't think he's making mistake or become arrogant when he stay away from his old circle.
Apart from gambling win, money is something that reveals your true self on what you are capable of doing. Many people are selfish but you won't know until there is a thing happening that will reveal the real identify of the like the gambler who ran off his gambling friends . Now is he associating with the guys who have some money but he couldn't do that before his winning, he sticked with his friends. He has inferiority idealogy and that is why he felt he has moved up and won't go to the gambling friends. Anyway, money is transient if not well managed.
So the question is, the people who claims the man have abandoned them and forgetting their long time friendship, when he have not won that bet what have they done for him, have they supported him in any way, even if it’s not financially have they given him any form of moral support which will help him reach where he is today. No body want to keep who can’t help them go far in life close to them, I have money now means I should be dreaming big and anything that will want to drag be backward I will have to cut those things up, so I believe that’s what the guy in question just did.
However, it depends on the level of friendship that exist between them because I know some gamblers just form clique while gambling because they share shame goal and aspiration which is to win big some day and this is fustered because they meet almost on a daily basis at the offline gambling house. So in such situation they may not be regarded as friends that are indepted to each other one way or the other but there are also true friends who have been through thick and thin, so you don't have to move on like that after all you guys where there together and putting heads together trying to summount the insurmountable financial huddles all the while.