Coinage, trust me, you "get it." But think about it. What are the numbers in the greysheets if not a reflection, at least, of the most recent "past performances" of the coins; and, what's their purpose, if not to influence our "investment" (or whatever you might call them) habits? OK, maybe "racing programs" would have been a better choice of terms than "scratch sheets." Then change it, see what I care.
No they can't, because the first U.S. government-issued coins are 215 years old. IMO, it's investing if you buy the coin with the intent to sell it for a profit.
For widget coins or low end pieces. The Graysheet is fairly useless for high end coins, thinly traded coins, truly rare coins, varieties, errors, or anything else out of the ordinary. And the grayshet originally WAS the dealer to dealer wholesale sheet. Dealers bought and sold from each other at bid and ask. Collectors were offered bid or even back of bid, and sold to at over Ask. Ask was the wholesale Ask, not retail. The sheet was only available to dealers. But collectors would get ahold of copies and try and worm their way into the wholesale market. And originally the graysheet was for sight-seen raw coins. Once slabbing came along the Bluesheet was created for sight-seen slabbed coins and the graysheet was still for raw coins. For awhile there was even a pink sheet for sight-unseen slabbed coins. But the bid and ask levels fell so low on it that that sheet was discontinued. Then the bluesheet became more for quasi-sight-seen slabbed coins, pieces you could still decline on once you saw them in hand. Prices fell on the bluesheet some as well. (It was interesting, for awhile slabbed coins sold for LESS than raw coins of the same grade.) So the graysheet became the guide for pricing sight-seen slabbed coins as well as raw coins. But it has still become a two tiered system because few people will pay the same price for a raw coin as they would a slabbed one.