Imagine if half of those viewers are not Prime subscribers and then sign up....
cha CHING
That is what Amazon is hoping for. I think their hope will be in vain. Unlike with Twitter or prior NFL game venues -- Amazon requires you to pay for a Prime Account at over 100 bucks per year. This works great for existing Prime customers (but only a small percentage actively watch the NFL). There is also a question if Amazon will require Prime users to pay extra for an "NFL sports package" (not disclosed yet).