You might even find that they "restrict" large withdrawals to buy some time to payout large wins. This normally escalates to players venting their anger on forums like this. (The good casinos will pay instantly)
Yes when casino is not able to redeem payment of winners, it usually leads anger and show of vituperation especially for off line game houses but I think that is also same with the online casinos which is why we witness some players coming here to open up scam accusations thread when they win and can't claim the money.
Therefore, there are points here to note on the reasons that casinos will not be able to pay winners because they become insolvent from bettors winning.
New casinos can have this issue because they are inexperienced in most cases including setting of winning limit. Usually it is difficult to win against the house but in a situation that the players is sufficiently good, there are limits set for a winning slip. Take for example in Nigeria, gambling companies like bet9ja, betking etc, they all have limit that a betting slip potential winning amounts to and anything other than such is not allowed by the system. The maximum payouts in bet9ja and betking is #40,000,000 which is ($53.3k). With such limit, there will be an assurance to redeem payouts and the company won't go bankrupt.
Again, new casinos that have no affiliate also may go bankrupt.