If Elon Musk open bitcoin casino would it overtakes Stake.com easily?
Elon musk is the richest man in the world with a net worth of over $245 billion, and cofounder of several successful companies all around the world (Paypal, Tesla, SpaceX, and shitcoin such as Dogecoin, Babydoge). So if he eventually owns a gambling casino, there is a higher tendency of it doing far better than all existing casinos, since he already has the funds to launch and organize effective adverts for promotions. And just like what @Adbitco said, it's policy about KYC will also determine the crowd that will flood to his casino
And then he can allow Paypal to play directly by connecting accounts to the casino. This casino will likely be popular along with Stake.
But this will make him spend a lot also compare to him just buying Stake.com instead. He can just offer the owner of Stake. Twitter was big and also offered a big amount. With $245Billion, I'm sure they can agree on an amount.