Feel you pain, sad but we can't do anything about it, your bad luck must have made up at least 2 people get their weapon at first time.
Maybe SE should secretly implement a rule that, the drop rate will be affected by people's bad luck, so if you are the one in the team with highest number of Boss fights and haven't got the weapon yet, the drop rate for your weapon will be increased.
So people will still have good luck and bad luck, but those bad luck ones won't be getting a desperate stage like OP.