i think it's partially due to men being more obsessive about stuff than women in general (i've never seen a female baseball card or comic book collector, for example). but mostly i think it's due to the fact that men have been brainwashed into the whole timeless style thing. makes us more likely to spend $$$ on something if we think that it's somehow justified by being timeless and outside of trendiness. which is not the case. we think we're smarter than we really are.
I was about to say, "have you ever seen a male shoe collector?" but then I remembered where I was A lifetime ago, I used to run gaming and comic cons, so I have met the elusive female comic book collector.
I think the big difference is that there is an idea floating around that women should save their money for accessories - it's what other women are looking at. So they buy cheap clothing that fills the landmines and $$$$ handbags. The woman who can afford a $100,000 to million dollar wardrobe doesn't want to spend time in thrift shops and doesn't want to risk eBay.
Men know that they can find better prices on the good stuff - so there are more of the competing for the rare Kiton up for grabs.