I suppose it comes down to differences in human nature -'Different people, different ways' as DH Lawrence once wrote. It's a bit like the fine art market; some will pay gazillions for an original, but if I like it, I'd rather have a decent print than pay silly money; but then I'd want to stick it on the wall and look at it, not hide it in a bankvault and gloat about possessing it.
In this case, I'd probably be doing a mental calculation during bidding. Do I need it? Do I like it a lot anyway? How much would it cost me in materials and time to make a new one? Can I buy a decent new one cheaper? For many Ebay tools, the price is cheap enough to allow for some fettling time and still end up with a good working tool (better than anything available new in some cases), and when that total cost is lower than a good new one, that's worth it. When the auction price becomes high enough, then for me the pendulum swings to the buy new or make one option.
In this case, I might want to have a look at it to see how it's made, and what it's made of. Then I'd make a new one (assuming I needed one, which I don't), which I'd sign so that future generations knew it was a copy. Then I'd hand the original to the collector and let him enjoy it's originality. That way, we're both happy.
Perhaps the happiest person is the seller. They've won a small fortune for what was to them a bit of junk. Provided they don't go daft and assume that every rusty tool is a potential goldmine, eveybody wins.
Funny old world, innit?