Don't get me wrong there are a lot of new casinos popping up in this forum and maybe some online casinos out there that haven't been on the forums because they don't know and don't have a team that can operate casinos using cryptocurrency payments.
There are several fiat online casinos in my country and I had a chance to chat with their support regarding the use of cryptocurrencies and their answers were all the same, that is, there is a fear of using crypto and also not having a reliable team in the field of cryptocurrencies.
But in the future maybe all casinos will start using crypto as their currency value and join the bitcointalk forum for promotion.
It seems to me we are getting closer to the point in which fiat casinos will be unable to ignore cryptocurrency holders anymore, gambling as a whole grew at a very fast rate during the pandemic, but it seems cryptocurrency casinos grew even faster than their fiat counterparts, and while in part this can be attributed to the smaller share of the market those casinos have, making it easier for them to grow, at the same time the number of cryptocurrency users is growing, which most likely will force some of those fiat casinos to adopt cryptocurrencies, even if this was not part of their short term plans.