In Thailand, there are strict laws that govern gambling. There only two types of gambling that locals and expats can legally do in Thailand: the national lottery and betting on horse races at licensed racetracks. Every other form of gambling is prohibited in the country.
Today, it's estimated that there are between 3,500 and 4,000 online casinos exist. As of 2024, they make aroundR$56 billion in revenues (gross incomes) a year. That is, roughly, $14.9 million a year gross income per year per one online gaming house.
Keep in mind that this is just to get your casino up and running and does not include your monthly expenses. Expect to pay at leastR$15,000 on a gaming license. The average price for a casino game software package is aboutR$200,000-$300,000. Web development might cost youR$1,000-$5000 or more.