I was thinking further about displacement behaviours and realised that the insecurity of inequality has been much greater in the past. I also thought about examples of behaviour that took advantage of those weaker than the person, or used power over another person to satisfy insecurities.
Amazingly enough, given my other beliefs, one thing sprang to mind as being more prevalent in the past and particularly prone to such behaviours, and that's religion. All the major (western) religions ensure that women are kept in their place, so that even impoverished men can feel some sort of superiority. This sex-difference takes me full circle back a few posts to the way I differ from most men in wanting a strong, independent woman rather than mere emotional support in all I do. There are other ways in which religions help people impose status hierarchies (the Indian caste system seems like an alternative to sexism).
The need to keep women in their place has always been greatest amongst the poor and disadvantaged, as far as my limited knowledge of history tells me, and I wonder if sexism can be yet another problem exacerbated by inequality. That seems an easy enough argument to make, but can we make a case for religion as well?

Obviously religions support sexism in their traditional forms, but that's not necessarily intrinsic to religion, but could be how they've developed because of the demands and needs of their adherents. But do people need to know about a God above who punishes the arrogant and honours the humble because of status issues? Is there something that necessarily links religion and poor women's rights because the appeal of eternal life for the humble is linked to the appeal of having someone over whom to exert power?
Is this link permanent, or can we break it in a modern, secular society with low inequality that therefore doesn't provoke status concerns in people who would be prone to them? Do we need to bother? Does less equality lead to more religion? The US is one of the most unequal rich countries, and has appallingly high rates of religion. Portugal is unequal, and is known for being a Catholic country; Wikipedia tells me that 84% of Portuguese call themselves Catholic, with an unstated number attending only important services, rather than regularly.
The Scandinavian countries are more equal, and are successful secular states too: 32% of Norwegian citizens believed that there is a god (in 2005), and between 31 and 72% of the population call themselves atheists, depending on the study. Perhaps this is why the right wing of politics hates the idea of promoting equality; it is intrinscially detrimental to religious belief. Certainly in the last 30 years, religious belief has become more and more correlated with right-wing politics. Before then, this was less the case, probably because religion was so dominant that it was rare for anyone not to profess some faith.