What do we lose when we lose the old ways?

What do we lose when various practices no longer are necessary? Is there a value in keeping up old things, such as old computer card readers or readers for other old formats of data? Is it worth knowing how to carve wood or throw a pot? Is it worth keeping typewriters and buggy whips around?

If you think there is a loss, then characterize the value of keeping people who can still do these things. What is the advantage of keeping old, obsolete technologies around? Is there some kind of spiritual value to maintaining the ways of the past? Or is the value more practical?