It can really help to decrease the gambling rate. But I hardly think that any casinos will be in support of this. The main motive of casinos is to increase the gambling bets in their casino and wants people to lose money; hence, why will they support something like this, which will decrease their profits? If also the government forces to apply this, then the casinos will allow multiple accounts from the gamblers and will advise them to deposit in another account if the other accounts get limited. But yes, it can really reduce the gambling rate addiction if implemented in a proper, transparent manner.
I don't think this has a big effect, even though there are some casinos that require customers to fulfill the KYC provided by the casino, of course they will fulfill it because what they want is victory even though it is difficult to obtain, also sometimes there are casinos that at the beginning of registration they do not provide KYC requirements but when the customer manages to get a big win and withdraw it and then there the casino provides KYC which must be fulfilled by the customer as a condition for being able to withdraw the winnings, of course the customer will do it, there is no way the customer will just leave his winnings right?
In addition, the number of casinos currently in circulation certainly does not reduce the chances of those who want to gamble, even if they are lazy about KYC matters, I think what they will do is look for other casinos that do not provide requirements to fulfill KYC, when someone already wants to gamble it is unlikely that they can stop if they cannot control themselves properly, especially with those who have the thought that they can win at gambling.
With this increasing level of addiction, I doubt that the existence of KYC can reduce the level of addiction, there is a compulsion that pushes themselves to meet KYC requirements like this and makes them not easily switch their minds with gambling that they already want to do, besides that with the current development that is increasing this makes it easy for them to access many casinos and look for casinos that do not provide KYC requirements.