The simple answer is that the price of fixing the dented top tube and cleaning up the (difficult to match) green paint explains the price difference. Add to that the fact that the 1975 is the color scheme I wanted, and in the size that fits me perfectly (and the three most important things about any frame is fit, followed by fit, followed by fit) the "10 to 1 ratio" -- in real world terms, try to find someone to fix the dent if you can't do it yourself (and I don't have that skill) or repaint it or clean it up to presentable standards for the $125 difference and let me know when you find him. (And good luck.)
It is amazing how many people 'know' what a frame is worth, until they can't find one in their size or in decent conditon.
Dave Novoselsky Chicago and Pleasant Prairie, Wi (who bought the 75 and is still looking for a Professional in his size in the 'classic' color scheme, and hasn't found one in decent condition other than the one he bought which got banged up by the good folks at UPS and was taken back by the seller to fight out the damages with UPS, and who therefor KNOWS what it would cost to put the Green 73 into what looks like the condition of the red and white 75 which was in the colors he wanted to start with.)