Problem with that is that Netflix is unwilling to raise the price or charge a premium for anyone. If Netflix did it for HBO, other content providers would want the same deal and Netflix would be up a creek.
Without a premium charge, Netflix can't pay HBO what they want. So we are stuck where we are.
They won't because if they did all the haters would claim Netflix is "raising" prices. They already dealt enough with that kind of bullshit before.