That is another reason to legalize. A street dealer doesn't know their product that well, probably has little relationship with the grower, and is many times just trying to move product, quality control any more than repeat buyers is not usually a concern.
Couple that with the places I've gone into in Oregon just to see what they are like and man, it's like going into A high class winery and then some. Top of the line product, growing conditions, location, organic LT grown on and on. These people love their weed and will spend a huge amount of time talking about it as it is their pride. Also, since it is legal and there are other dispensaries, if the product isn't up to the consumer liking they can just go across town.