No. The analogy doesn't work. In the marijuana industry, the marijuana plants don't get a choice about whether they participate.
If you remove trafficking, exploitation, and coercion (and especially if I'm including the coercion inherent within a capitalist economy here -- IE: you have to work at SOMETHING or you'll fucking starve) there are very, very few women who are willing to engage in sex trade work. If you run a brothel, even if prostitution were legalized, the majority of women working for you would be either trafficked, coerced, or women who have no other choice due to some combination of: drug addictions, mental health and lack of education.