If one is not consistent in gambling it is possible not to win or maybe to win only few games and sometimes when the number of loses is so huge it's just as if one has never win any game in gambling. But if it is a gambler that consistently plays gambling I don't think it is possible not to win gambling, it is possible that loses is more but there are wins that one would be able to remember. Winning gambling is based on luck but experience also plays a role in the outcome of every game, and consistency in gambling can only give one a better experience to understand how gambling works .
Even if someone doesn't gamble regularly, it doubtful that he never wins a single game. Sure, we can't ensure whether we will win or lose, but never win a single game sounds no sense. If it really happens on someone, he truly has no any luck.
You're right, most gambling games are luck-based. That's why it is difficult to determine the wins or losses. However, I'm very sure that each individual won't be always unlucky in gambling, there should be the time for a lucky day. After gambling few days or weeks, there should be a single win to get. Sure, there will be more losses because the house will always win in the long run.