What could happen in extremely rare cases is that a whale gets lucky and sends a casino into bankruptcy. However, I would not have come across such a case yet and you would probably actually need someone with a lot of Bitcoins ... and a lot of luck.
I don't think so that's how casino business works as they have house edge and also liquidity with them to pay off any win and going bankrupt means they should not have entered in this stream first of all because you estimate every aspect before registering any casino.
well, if the casino is already established and strongly running indeed that there will be no bankrupt to happen , but those newly operated and sadly experienced a Huge win from new players, in that sometimes comes the dishonesty from the site and turning into not paying and become a scam one.
but with Roobet.com that has already tons of funds inside, Am not sure if any whales can make them bankrupt , not at least from my knowledge and understanding .