2 weeks later, at least 500 more fights done. Still no drop. So I am at somewhere between 1400 and 1500 consecutive fights without a girl drop now o.O.
With that 0.5% chance above to win a girl in fight 1400-1500 fights should give between 99.9104% and 99.94572% chance to get at least a single girl.
So I am slowly reaching the "lottery winning chances" of not getting a girl in a long consecutive strike of fights.