It's quite a bit less common on earth than either Cobalt or Lithium, and currently pretty much all of it is used for metallurgy or lubrication. Roughly an order of magnitude less common than either Cobalt or Lithium (~20ppm vs. 1.5ppm).

EDIT: Also, per wiki, we produce almost 2x the amount per annum of Moly than we do of Cobalt, so presumably we're a lot closer to hitting a ceiling than we are with Cobalt/Lithium.