Casinos are businesses & not charitable organizations, they seek profit from what they do, from that simple logic we should have got the answer. I remember one of the users here who had an interesting thread, he made an interesting answer in his FAQ.
Q: How much money does an online casino earn?
There are tons of casinos that are publicly trading, so their earnings are available to the public. For an example, you can Google Betsson AB Quarter Report, and you'll see that they are ranging around 50 Million per quarter, but they are also a huge operation that eats a lot of money by itself. Smaller operations usually earn anywhere between 250.000 to a million per month, but since it's such a volatile market, you have to have a fat war chest for hard times.
It's still an online casino only, what if you operated a physical casino too? that's why gambling should be based on entertainment, otherwise you will be destroyed. You can visit his thread
[1] & see many interesting questions & answers or raise questions that make you curious about all the operations there.
[1]
https://bitcointalk.org/index.php?topic=5482508.0