Do you guys have any thoughts on this... plague?
This isn't a plague, initially casinos didn't develop several sides independently. They mostly hire a team or buy templates on development sites, no professional developer is willing to risk time on speculative results. However they can take more risks on marketing to build the brand, the result as you have seen most, is that the offer is better than the reality.
yes, I think it's true in majority of cases because not every casino will be profitable business,
so it is important to take low risk like buying templates, most of the work doing inhouse like people for customer support, etc.
also the good casino called by their sites interface and their support, the code is mostly bought by third parties. which may be edited with more feature if the casino become successful in the future.