Possibilities like this is one of the major reasons why I always avoid new and small casino, because they either may turn out to be a scam or if you win big, they will have difficulty paying.
I am with you on this very rule of avoiding any upcoming casino or at least if perhaps I decides to test their service I made sure to gamble to win such amount that it's not too high which I am sure can be paid should I be lucky to win. Most of these new casinos really don't have that much amount on ground to pay if a gambler hits it, they may really not be scam casino but they just by financial capacity at the time not able to payout such amount all at once but can only stretch the payments which might take too long for any gambler to accept it that way.
In a situation where they have to stretch payment, the gambler should have no choice but gladly accept it because it's definitely better than getting nothing at all, and what if the gambler hadn't won the game, wouldn't he or she still go about his or her business and probably forgot that he or she lost a certain amount of money to a casino at a certain time?
So, like you said, it's very possible that a casino may not be a scam, but are simply financially incapable their winner in lumbsum, so the best they can do is divide the payment in batches, in this type of situation like I've said before, the gambler should gladly accept it because If I am in the shoes of the gambler., I will accept it too..
If I really want to have the money ones, an idea would be to open a seperate account where the casino will be paying in the money every week or every month depending on the agreement, I won't touch the money until it's completely paid in full.