About $5,000. (Sorry, I had to)
But here's the thing, many who claim to "make" $5,000 are either full of shit or they "make" $5,000 as income, not profit. $5,000 income on drop shipping isn't that hard, if you take just enough margin to make a buck per item you can hit $5,000 easily. You'll be making like $300 a month but you can tell all your buddies, and more importantly the people you want to buy your eBook, that you've made $5,000.
If you take out the technically true but mostly lying sacks of shit, I'm fairly confident the numbers aren't that far apart. The ones claiming to make $0 often want to be spoon fed, so that's likely most of their problem. They just don't understand it's still a legit business with outsourced logistics.
So between the people that aren't lying and aren't making $0 because they think it's "put items on a website, sit on beach", the numbers aren't going to be that far apart. Drop shipping isn't exactly rocket science, you're running a regular retail business with outsourced logistics and need to do everything a regular business does.
Those who understand that will make $5,000, those who don't and think it's a way to get rich doing nothing will make $0.