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 also think luck is a huge factor in this game. Since cockfighting is modified by equipping blades on the legs of the rooster, other rooster are not comfortable wearing it so as a result there are some incidents of self-afflicted damage that can result in the death of a roster. This sometimes happen when the dominant rooster shuffle the almost beaten opponent that is lying on the ground. The dominant rooster often hit its neck that can result to insta-death of the rooster.
Another case of luck case is the fighting strategy of a cock. Since most owners are not aware of how the cock fight, there is a chance that their rooster fight style is countered by the opposing rooster's fight style. There are lots of cases that luck can apply on the cockfigting game. One that I experienced was that the blade was wrongly equipped on our rooster making it not deal damage even though it should be a clear hit.
Yes, if it is not a luck-based game then what is it? I think it's clear that it's classified as a luck-based game because even if your rooster came from a strong breed that previously won different tournaments, its chances may somehow increase but its vulnerability is the same as the game is based on who will survive last or who will inflict the most stab from that blade they're equipped.