Bachus, I think it's hard to assign a time to master an instrument. One must consider natural talent, desire, self-discipline (think practice), external support (parents, etc.), and (VERY IMPORTANT) quality of instruction. Six months of Bass lessons is NOT going to turn you into a Ray Brown or Jaco Pastorius; why, because it's not only about mastering the instrument, it' also about mastering the music you're going to play on that instrument.

The other thing is the required DEDICATION. Like most here, yourself included, few are willing to risk their livelihood on a career as a full-time musician (with the exception of music teachers in the conventional education system). Most speak proudly of their 'day job' as though music is little more than an (expensive) hobby; something to "impress chicks", or feed their latent childhood fantasies of being a 'rock star'. True, everyone's motivation is not the same but in most cases the drive one sees in successful career musicians is missing. Just my thoughts on the matter.

chas