But the biggest reason is probably that its hard to make a skill-based game into something luck based.
Cockfighting is more of a luck-based game though your bird has a high chance of winning if it is well-trained but in the end luck should be on your side most of the time to win.
Is it though?
One rooster is not the same as another rooster. If anything that is what I imagine to be one of the most exciting parts of the game? To bet on a better rooster? Thats why in real life cockfighting the strong roosters are very prized. If you wish to emulate that experience and offer it as a game on a gambling platform, then you cannot make the digital version luck based. Otherwise it just becomes a simple dice game but with animated roosters...
Not that I am an expert in cockfighting. Far from it, actually.
I'm also struggling to determine whether if it's luck-based game or not, I know what you're trying to say and I got your point. It's just sometimes, even the strongest rooster will get defeated unexpectedly and surely there's a lot of gamblers who will lost that bet because no one would expect that it will get lost. If you're particular about this game, then you already knew that there's a calendar that the bettors are looking and the type of the moon of that specific day/night. Of course, there's no guarantee that you will win if you'll base your bets about it but there will be some times too that it will really go through.