PM- No one- as far as i know- wants to be a ganav. the discussion about ‘kvitlech’ ,and dreidels too, is whether they could be played on Chanukkah. Yup- “mesachek bekuvia” (which are the dice, BTW) is considered gezel because it is an asmachta and not a real giving by the loser. However, you will have difficulty convincing me that in a game played with dimes and quarters on chanukkah, that the person losing a few dollars does not give them away volultarily. Once this is apparent, it is not an asmachta anymore, but a gift.
The mishnah in Sanhedrin is talking about professional players- as there are many today- and this is why they are posul le-edus. Additionally, if you gamble in large sums, the logic of asmachta makes sense. But if you play with pennies or even quarters, the actual sum is rather small and can be accepted as a gift.