That they believe their own BS. You can negotiate with someone knowingly lying to gain advantage, these emotionally incontinent natural midwits can barely conceive that there might be another perspective from their own or that something being high status and popular doesn't make it true.
Alternatively, that they are the only option available. If there was a third sex or an AI-powered robot gf, their monopoly on sex and their bargaining position in society cease. With how much less they contribute to anything from science to total tax revenue, suddenly they would be in the position of the beggar, needing support from people that no longer have a use for them.