I have no idea how he pulled it off, but he did.
It's not mysterious. He sells a regular, 12-oz. cup of coffee (regular or dark roast) for less than the local Dunkin' Donuts (about $1.60 in my neck of the woods). And it's waaaay better coffee.
You can add all the weird stuff to your brew and get the price of your order up to multiple bucks, but the distinguisher over Dunkin' really is a consistently good-tasting product at any price level and a cleaner, more comfortable place to sit down. Service is generally quick and gracious either place.
I quit Starbucks when they thought they knew better than me what I should think. Refuse to drink their colored water ever since.