I think one of the reasons for that is you can take a card to league to show off to everyone, where a uncut sheet might be a little hard to put in your binder So maybe there is not as much of demand for it since it is hard to show off.
I saw some fossil rare sheets that sold pretty cheap.
I would have bid on them if I was aware of it at the time.
But a rare sheet is not a holo sheet...
It was a holo sheet of like over 100 1st edition machamps. Got it from the Gencon thingy last summer. (meaning WotC-era, but its an uncut sheet regardless)
I guess that does make sense since you can't fit it in your binder and show it off. Heh.