Sheep mentality: How many people are attracted to an form of High Art only after the masses have declared it as such (and they pay accordingly to own such at that point)?
The 'eye' belongs to one who can determine such an item outside of 'the market' and that one is greatly rewarded if that same market discovers this item later.
That said, Fine Art is Fine Art and a well honed eye will find such items on its own without requiring the validation of the masses. As well, the true collector collects. He doesn't 'invest' and (technically) cares little about the after market.
Same agrugment that we see in threads here regarding the valuation of wines (valuations increase to a point one questions whether to consume) can be applied to Art.