first of all, oranges and apples grow on trees.. you'd have to wait a long time to get the first piece off..
broccoli and potatoes require the right type of soil and a lot of maintenence..
marijuana is a weed.. and grows wild.. and begins to bud within months..
Im not saying their wont be anybody to buy manufactured weed, but most would just grow it.. think about it.. if weed was legalized tomarrow, you wouldn't consider just growing your own?