No film now or in the near future will come close to Titanic, and to ascribe that to movie piracy is simply self-deception.
Also remember that whilst this will make ROTK the second highest grossing film of all time, that makes it far from the second most successful film of all time.
Adjusted for inflation, even Titanic is only 6th on the list of most successful films- above that being Ten Commandments, E.T, the Sound of Music, Star Wars and Gone with the Wind- all bigger films than Titanic, a mark ROTK is not close to yet.
A long way to go- and ROTK will only go so far. It can aim for the top ten in that list, perhaps.