Every single one of those trades has a component of skill, and while a reasonably intelligent and cooperative person can be made barely competent at most of those things within a day (and I doubt that's true for some, like call center agent), an experienced and learned worker in those fields will demonstrate superiority in most cases. However, that doesn't mean we need licensing.
You can't take a person off the street and have a fully functional barber in a day. The professions above, you can.