This is very clear and logical point that is major concern for public health experts. Yes constant rise of new casinos and gambling platforms pushed by competition and creates ripple effect. More gambling options lead to more aggressive advertising which makes gambling seem normal and harmless. This easier access and constant publicity can lead to more people trying it increasing risk of gambling addiction. And it is logical to think that fewer casinos might mean less addiction but real issue is not just number of options but how well they are regulated to protect players.
Truly, the normalisation of it definitely leads to more adoption. You brought up an excellent argument that's been rattling around in my head as I see more and more ads for gambling and big streamers gambling on stream to a younger audience. The culture and regulations around gambling matter much more for the adoption than casino offerings to me. Casino's having to compete to stand out is definitely better for the consumer but I don't necessarily see adoption increasing much as a result. Whereas if there's more people who see it as just another source of entertainment on a night out, that's where the real crowds will come from.