They won't. Their days are numbered.
Building the future is hard and it's messy. Netflix has been taking it on the chin this year as they've passed through a really rough patch.
In the end, though, I'd put money on Netflix existing in 2020 before I would any given broadcast network. TV is dead.
Netflix is trying to redefine distribution. They're not going to win by placating the dinosaurs of distribution's past. If the Arrested Development deal works out, production companies may see that they have new options for financing their projects and might get better opportunities to reach an audience than they'd ever get on TV.
So it's simple: take the issue by the balls and control your destiny or bow and scrape before moronic suits who don't understand technology, hoping and praying that they won't change their minds each time a licensing deal expires.