Sometimes the reason why gamblers used to see there potential winning as there's is purely because of over confidence. They fail to understand that gambling is a game of luck and as such it will be wrong for any gambler to treat there potential winning as there's. However, I have seen scenarios were the reverse of what you actually explained happen.
It's quite understandable that many people gamble, and many are confident that they can win big on a single bet. However, this often leads to addiction, making it difficult to break free, and ultimately ruining their finances because most of their money is spent on gambling.
Therefore, we must be self-aware. Betting within our means is the right behavior. For those who bet beyond their means, gambling is no longer just entertainment but rather a means of profit.