If those 3 billion minutes were watched non-stop 24/7 for the paying subscribers it would make at least $486,111.11 for Netflix assuming the subscribers paid for the cheapest subscription at ~$7. That's still a lot of money, but they also pay for their own upkeep, servers and much more.
I know most people don't have the cheapest subscription, and also that they don't watch 24/7. But it puts into perspective that Netflix doesn't earn that much on one series.
To add: they also make their own shows and productions and they pay to put shows up on their service that are not their own productions. I don't know what a show like suits will cost to be put on Netflix, since they don't produce the show, but I'd imagine that's not cheap. And I guess the writers get a percentage of the money earned on the selling of those rights (depending on the contract they have with the original studio)
And the paying of the writers is in the hands of the studio selling the rights, not Netflix.