There are two different things. In which countries do people spend the most money on gambling?  The second thing is which countries have the most people gambling in them. The statistics from the article show only the first one. This only shows that the population of these countries is richer on average. However, there are countries where the majority of the population gambles, despite the fact that the average population is poor. By the way, for a poor player, $10 can be just as significant as $1,000 for a rich one. So the country's economy affects the average gambling spending. But the prevalence of gambling among the population may be the same as in poor countries.