How religious the country is will also determine their gambling habits. It doesn't matter how wealthy the people over there are or how vibrant their economy is, if the country has more religious population their gambling activities will be extremely low compared with countries that doesn't care much about religion. So this should also be put into consideration when deciding why some countries gambles more than others.
Religion can be a big factor affecting the mindset of the people and influencing them not to gamble. But I see that money (income) is one reason why a rich country gambles more than a poor country. This is not just talking about the population but also the capacity of the individuals to spend on gambling. They don't gamble to win but just to enjoy their lives. It was a different story from those who live in poor countries, where they choose to risk and gamble for the sake of money.
In poor countries gamblers often gamble to double their money and they easily get addicted. Due to the strong religious sentiments in those countries they show a negative attitude towards gambling and a section continues to gamble despite strong restrictions. In my country due to the religious sensitivity of the people, they show reluctance to gamble and they avoid it. Another section of them enjoys gambling in a different way and they gamble regularly. Most of them show interest in physical gambling but in modern times many new gamblers play online.
The differences that are seen between rich and poor gamblers are part of a natural process that is seen in most gamblers, but I think that a significant number of rich gamblers play to make money, but many gamble for entertainment. And conversely, poor gamblers play almost mostly to make money.