Why do you assume that Sunday Ticket will always be there? Making games available a la carte almost requires dissolution of Sunday Ticket. This is all speculation, but I'd put my money on the NFL generating more TV revenue without Sunday Ticket and offering themselves (or allowing networks) games a la carte. The big driver here is access. DirecTV only has 20 million subscribers. 280+ million people don't currently have access to Sunday Ticket and many cannot switch even if they wanted to. IMO the only reason Sunday Ticket still exists is because the NFL doesn't want to open the 'a la carte' can of worms with the Networks. They just let the gravy train keep rolling.
Personally, I'd consider an a la carte package for maybe $100 a season. There's no way in hell I'd ever switch to DirecTV and pay whatever they are charging to get ST. I'd wager there are a lot of people in my place.
Let's make a guesstimate here:
It's estimated that there are 2 million ST subscribers (10% of all DTV subscribers). If the accessible market for a ST/game package went from 20 million to 100 million (there are approx 115M households in the US, assume some people don't have TV/internet access). That's a 5X increase in accessible market. If the game package subscription rate stays the same, that would be 10 million subscribers. At $250 per subscription, we're talking about $2.5B. That doesn't even include bars and public places, which may a much, much higher rate. Thousands of dollars per license.
All guesstimates, here, but you can see how it really wouldn't be *that* difficult to cover the $1.5B that DirecTV is playing them.
They'd also have the option of offering all kinds of different packages, 2 non-local games per week: $100/yr, 5 non-local games: $150/yr, Full access: $250/yr, $20 for an individual game, etc. etc. It would be a big undertaking, but eventually I think they'll get there. They have no incentive now because the money is coming in at a ridiculous rate. As soon as things start leveling or going backwards this option will come up awfully quick.