The whole basis of the MJ plays right now is the uncertainty of the legal status, and the work-arounds that innovative companies/people are developing. Folks will always find a way to make things work, no matter what the rules are. Who knows what will happen if the feds ever take away the shackles, and let legitimate companies in (Banks, Big tobacco etc).
One thing to consider is, the culture that is developing by being quasi-legal will influence the future. Even when the big boys jump in. Kind of reminds me of the current craft beer phenomenon, eventually the big breweries will slowly but surely buy their way in, will that be the route that the big tobacco etc. will take when this becomes federally legal?