i think its because it is human nature to require something that is available for our senses in order to see that it exists and assign value to it. as kids we look at, feel, smell, and try and eat pretty much everything in trying to evaluate it. we're not that much different as adults.
if we can only see the product, or only hear the product, i think that by our own distinct human nature, we're going to want to value it much less than something we can hold in our hands and stick in our mouths. even if its the exact same thing, just printed out in tangible media.
it'll take some time to get used to it, but eventually the entire culture will acclimate to it. but thats what it'll take -- the entire culture making a conscious change, and everything appropriately changing with it. as an example, the younger kids and adults now are much more used to it than our parents (and bosses) are.