If people could agree on some source of unbiased data about average wages that updates frequently for a job type, then there certainly could be (cash-settlement

If people could agree on some source of unbiased data about average wages that updates frequently for a job type, then there certainly could be (cash-settlement only) futures based on that value. What seems relatively unlikely is that you will find people willing to offer physical settlement futures! The market would probably also be somewhat shallow, being more speculators than anything else. Basically only groups acting more like insurance companies would be willing to add much to the depth of the market, and obviously they would sell such futures at such a steep premium that is unlikely to be a very useful hedge.