Interesting nobody has mentioned couriers. From what I've learned 10th hand, most big-time patrons/bosses/capos never touch dirt themselves, they merely arrange. Literally had to reinvent the criminal legal system because of it (RICO)
Also, a little comment on movie drug deals, 8/10 times the drugs are fronted, even with new connections, and when they aren't, cash and dope are rarely in the same room with the same guys. Often 1 crew picks up dope, another drops off cash. And definitely, nobody is hand-counting $500,000 in 100s in the middle of a coke deal.