Sure, all contracts are re-negotiable in theory, but think about the reality of the situation. CBS and Fox's deals combined are $4.3 Billion a year. Do you really think Apple would have paid what it would've taken to get CBS and Fox to agree to the things Apple wanted to do? At $2 billion a year, Sunday Ticket would've been a huge loss leader. At $8-10b it'd take to get the kind of deal they wanted, Tim Cook would've been looking for another job

And, the NFL also has non-monetary targets. They want to keep the games on broadcast TV to maximize the reach. They are not a niche league like MLS that's willing to be 100% on streaming. The prestige of the NFL is going to keep it out of a purely streaming product as long as there are TV stations broadcasting free over the air