“Past crackdowns in Cambodia have often left the financial and protection networks intact, allowing operations to quickly reconstitute.”

Not to mention there might be some profit to be made.

There is a recent book/report called Scam, about these scam compounds. Despite being illegal prisons / forced labor, they create a lot of economic opportunity in nearby towns and villages providing supplies and (paid) labor. Also, scam compound victims often get little sympathy, with notions such as "they are gamblers", "they want easy money", or plain old discrimination because they are foreigners.

I don't know how much of the money they scammed stayed in the country.