For those willing to pay the sky high costs of government regulated and taxed weed to avert risk, some will go that route.

For those willing to pay black market rates which will be substantially lower, and are willing to accept more risk buying from unlicensed users, sme willgo ha route.

I suspect majority of current users will stick with the black market route, because they will be in position of legal weed after a black market purchase anyways.  Cops won't be able to determine where you got it from. 

These whole legalization thing will only serve to increase costs for everyone, and increase roadside sobriety checks and the resulting charter rights violations and unlawful false arrests as police fumble around making purely subjective opinions on if you're impaired.