It is funny to read all the comments.

The last two events i have been Luck God, since i have obtained all girls. However, for instance, i obtained nothing in Valentine and Spring event.
Luck is luck and random is radom.

And although it is something frustating, if they x3 the drop rate you have three times more possibilities to get a girl.

On the other hand, and a suggestion, i think that they could increase the drop rate such as the player is playing until a maximum. For instance, i do not know the exact drop rate, but if the drop rate is 1% they could increase it until 5% given X games. Although it keeps being random, the player is rewarded.