I think that it depends wether you are a collector or just a woodworker that's looking for a good tool.
Collecting tools is like collecting stamps or coins, it is not only about having that speciall model, but also having the same model of the following year with that slight difference, and the next one with that another difference, or the same model made in USA, UK, or other country. And so forth.
Stanley planes for instance get much higher prices on Ebay if they have the original decal on the handle, the better its condition the higher the price, same happens with coins or stamps.
I'm no collector at all, my only regret is that collectors are ready to pay that much and even more to get a piece that it is missing in their collection, that leaves those like me and Rob and some others who are only looking for a "user" affordable plane somewhat at their mercy.
Then there are those who make bussines buying and selling tools, and who pay peanuts to lonely patternmakers widows for their husband's tool chests and sell them one by one at ebay or other places.
My two cents