It turns out that clothes are particularly hard to model. The ways fabrics drape, fold and wrinkle are complex and poorly understood. Add to that the play of light on and through fabric and you have a very computationally intense problem.
Hair is even worse, to get real looking hair you have to model every single hair, make sure no two hairs overlap, each hair has it's own subtly different color, reflectivity and transparency, and it varies with angle and along the length of each strand. And the play of the light interacts between the hairs and changes with every motion.
Yeah, those are the things that are going to keep actors and reporters in jobs for a long time. Even when they get the programming right it’ll still take forever to process and render.