In my town, there were five Dunkin Donuts owned by one guy. He started from very little, and worked his way up to a ritzy neighborhood.
Then he lost it all when the government leaned he was using undocumented immigrant slave labor. (It was pretty damned obvious when no one spoke a word of English and understood the word "cream" or "black" or "coffee")
I think this is a common thing in the American dream. Maybe one guy used illegals, maybe another guy used illegals for season farm work then murders them and burries the bodies. Odds are a LOT of businesses start off from drug money.
Sure, a few make it from bank loans, but consider the risks involved of working within the system as opposed to gaming it. How many businesses fail?
How much does it incease your odds of success, if you have a nice nest egg from cocaine or crack sales?
Of course, this also means a nice chunk of businesses have ties in organised crime. If they aren't outright owned and run by them, they certainly have major investment from their money.