In my opinion, it is just a matter of time because I think sooner or later most casinos will do the same but I doubt that other casinos can offer the same bonus like what offered by Stake but if other casinos also do not want to lose their loyal players then they may try similar thing but maybe less amount or maybe different offer.
We have guessed this since a few years ago and for this year Stake.com became the first to do it while other casinos may be preparing another plan
One thing I worry about in another casino is that they trap users so when request for withdrawal, the user is required through KYC this scenario often occurs to force users
Instead of thinking about bonuses but they have to think about the balance

this means we must be more selective in choosing a trusted casino.
You're 100% right here as there are many casinos who give the false illusion that you can gamble with KYC and they will allow you to make an account, play and gamble but not withdraw. Yes, you won't be able to withdraw until you pass the KYC. So gamblers should focus on exploring the trusted casino and one feature of those good casino are that they will always inform you of the right policy about KYC so there would be no surprises at withdrawals.