First is that, there is no statistics anywhere showing that a lot of people are interested in betting on cockfighting, at least, none I know of, so in case you have such data on your disposal, please feel free to share it with us.
Secondly, take for instance that cockfighting becomes legal in every part of the world, that is, both international and local gambling casinos take cockfighting up and open betting on the game to every gambler out there in the world, trust me when i tell you that betting on this game can only thrive for a very little time, let's say a year to two, and gamblers will start losing interest, why, because the life span of cocks are very little, and this will not allow gamblers to make a proper analysis of which cock stand a better chance of winning the fight before betting, this simply means that, majority of the time a gambler is betting on this fight, it will always be the gambler just guessing, no concrete assurance that he or she is sure of what he or she is betting on.
This can make gamblers lose interest in the shortest period of time, this is why i do not that a lot of people are willing to bet on cockfighing as you said.
https://www.thejakartapost.com/culture/2023/02/27/cockfighting-still-a-popular-blood-sport-in-southern-iraq-.html
https://theconversation.com/cash-for-the-winner-the-loser-for-dinner-cockfighting-in-timor-leste-is-a-complicated-game-131027
https://en.wikipedia.org/wiki/Cockfight#:~:text=years%20of%20prison.-,Cuba,also%20banned%20underground%20cockfighting%20pits.
https://taiwantoday.tw/news.php?unit=12,20,29,33,35,45&post=22471#:~:text=In%20Taiwan%2C%20cockfighting%20per%20se,modern%20and%20modern %20Western%20world.
Maybe there are many more in other countries that I don't know about.
In some countries, cockfighting is legal and can be found in my sources. It may not exist in international gambling casinos because cockfighting is only popular in certain countries. So you won't find it in other countries, and you might even find that some countries prohibit cockfighting.
I'm sorry if I'm wrong.
So for that, a few time i have to just read about it online and also watch some videos about cockfights, but even at that, the game is highly unpopular and its research results are not easy to come by at some point so this makes it hard for us to properly understand what the risk for this game is and how to handle them and what are their revenue generation or threat to an animals life.
The risk of cockfighting is that the fighting cock could die or be disabled. And that will be detrimental to the owner. I don't know what the owners will do once they discover the fighting cock is disabled. Maybe they'll slaughter him or something.