So every bet made are being placed on the Blockchain, which makes this a trust-less, immutable and unbreakable system. (Well, some miners have found ways to reverse bets and that lead to the closure of some sites.)
those on the blockchain bets often had the same issues with hackers and abusers since they require to be service opensource games as well. Hence, not everyone would really dare to take that risk when the current gambling is already secured and entertaining enough. Onchain gaming can be an innovation, but when such innovation tends to be a risk, it is better to use the normal platforms and make it as entertaining and secured as it can. Transparency isn't always the winner in gambling.
In the first place, they will not go obsolete if they are not abused and there were no flaws in their system but there were flaws and the current model proves to be a better one, secure for both gamblers and the admins, the one thing that we don't like is the KYC, KYC should be based on the trustworthiness of the casino, if the casino is reputable I'm ok with KYC as long as it meant to verify abuse or double account.