BS. Just hire better artists. It sounds like hand-waving, but I've worked with both kinds of artists. You're building games, so if you focus on only hiring artists based on their portfolio you might end up with a bunch of stubborn artists who need to be hand-held and worked around constantly. If instead you focus on hiring artists who are good at art AND who can demonstrate a propensity or desire to learn new workflows and and to be flexible, then you'll end up with a bunch of team players.

This is a common complaint about artists, but it has more to do with culture and expectations than anything else.