Steel needles can rust away to nothing. Broken ones are sold for scrap or melted down to make something else. Sheaths that are no longer used can be given to a museum, but needles may be passed on to the next knitter. Sheaths may be carved in patterns. Needles look dull and ordinary. Sheaths can have the date carved into them; needles can't really be dated except by where they are found in an archaeological dig; family legends are notoriously unreliable. So museums have had little interest in old knitting needles.
If you drop a stitch, you use a needle or a pin to pick it up, and you never admit to anyone that you were so careless. Crochet as we know it was not invented until the 19th century. (However, if you're Portuguese or Spanish or southern French, you're using needles that have hooks on one end anyway.)
=Tamar