Big win on a slot is a couple hundred grand pre-tax. Not that great, even hitting the major companies until banned from all will get you in the low millions pre-tax
The big casinos (with the big jackpots) are owned by one of a half dozen companies. You’ll get banned nationwide real quick from each if you get blacklisted. They also coordinate a bit so you cause a big enough stir and you’re done at all.
Then you’re stuck running your scheme at little tribal shops and strip mall gambling halls not worth the effort