Beyond the reasons mentioned in the Op I find a much important factor that keeps gamblers skip the KYC process is the fear of governments. Someday if governments request to submit the data of each and every user, our information gets revealed with the
amount wagered in total. Some foolish governments might also levy tax taking it as a proof of spending though most games lost.
It's not really about the gov't but it's simply because we don't want to be exposed and we don't want the casino itself to know who we are.
The reason why we used crypto to gamble is because there's no need for certain documents to verify in able to gamble.
Frankly, there are reasons why we don't want to reveal our data to others, and government could be one of the reasons. I myself, only submit KYC whenever there is no other way but submitting it and it should be outside gambling business, like what I've done in my local exchange. Btw, in gambling, instead of submitting my data, it would be better to leave gambling completely.

With exchanges, usually its normal compliance already for crypto folks since we have no choice to exchange our bitcoin into cash. That's why we have to follow.
Unlike in casino's, some will require you to do it if there's something wrong on your activity.