I remember people trying to use the cloth room for hair back in the early days of Firefly. I think they mostly just textured fairly large pieces of cloth to look like hair. For certain styles, it was okay.

Dynamic hair can be useful even for still images. Even the best hair doesn't have morphs for every situation. This is Kirwyn's dynamic hair, made longer and with a glossier shader:

There really was some nice work done with dynamic hair years ago. Kirwyn had some fantastic ideas, and there were a lot of different shaders that ranged from realistic to shampoo-ad shiny. But really, there's been no improvement in the Hair Room since Poser 6 or 7. (I think the above image was rendered in Poser 7.)