First by restricting just how early it could get videos, then by making them pay for streaming on every user, not just those who stream. I understood that to be the whole point of the ill-fated attempt at splitting the company, in fact.
The truth is they aren't trying to kill Netflix they're trying to maximize profit which is what every company does. They are delaying movies to Netflix because they've found people will buy the movies from iTunes during that time period.
If that will kill Netflix it's their job to say "hey, we're a revenue stream for you and we're going to go away if you delay these movies" and then a negotiation will ensue. This is how capitalism works with each company trying to make as much money as they can and companies negotiating with each other to do so.
Having said that I've always believed media should be treated as a monopoly and regulated accordingly. The current law treats media like just any other product where the free market can decide the price. This works with most products because there isn't that much of a difference between one brand of Vanilla Ice Cream and Another. But there is a big difference between different bands and since labels sign bands exclusively they should be regulated like monopolies
I believe there are compulsory licenses for sound recordings. It could be interesting to make all copyrighted works subject to something like that, but I can't imagine the details required to make it workable. Larry Ellison would probably have a heart attack...