As The Guardian points out, if companies refuse to release films or TV shows in US and UK at same time, they only have themselves to blame for piracy.
This may sound a bit harsh but if you want people to buy media, you have to offer it for sale. If it's not for sale, they won't buy it, but many of them will still want to watch or hear or play it, and will turn to the dark side of the internet to get for free the media that no one will sell to them.
This isn't a surprising research finding. Everyone who's ever run a business or worked in any kind of sales job knows that rule one is to make a product that people want and then offer it at a price they're willing to pay. Doing this won't always make you rich, but no one ever got rich without starting from there.