I doubt gamblers that already playing for a long time will opt out of that gambling site if KYC will be implemented. The trust is already there and the reputation of that site is now on the highest level. There should be no hesitation for these players to continue playing on that site even if KYC will be enforced.
That was though far from happening for now. Instead of being worried, let's enjoy the moment to play in our preferred gambling site without a KYC. Don't consider playing in a casino that was new in service if KYC is mandatorily implemented there to minimize the risks of identity theft.