With Directv, it's not really about a profit margin, per se when it comes to NFLST. They know that it's a good carrot to dangle to new customers but it's really more about customer retention. My monthly bill is about $145.00 a month. Now, in a world of cord cutters and people seeking a better deal, it's in Directv's best interest to retain me and the $1500+ that I'll pay them over the next 12 months than it is to play hard ball over a measley $350.00. Some may say that Directv is just taking it in the shorts by giving it away. Nothing could be farther from the truth. Directv has to pay that 20 Billion whether I subscribe or not. They're on the hook for the bill. They're better off keeping ME (you, us) happy by keeping us as customer's to help mitigate that 20 billion dollar bill than they are by pissing us off and losing the $1500+ (times how many million subscribers?) I'll be paying over the next year.
Here's something else Directv doesn't want to admit or face anytime soon: They're a dying industry. It won't be too long in the future that cable and satellite companies are going to go the way of the landline telephone. Some people still have them for various reasons but most of us have "cut the cord". With this in mind "customer loyalty" is going to be a cornerstone of "keeping the doors open". Now, don't get me wrong ATT/Directv are going to do everything they can to stay competitive in that word (including streaming), but with so many companies offering streaming services, they will no longer be able to charge my $145.00 a month. There will be too many options available provided by a jungle's worth of companies for them to get away with that price tier for very many years longer.