A question worth pondering, indeed.

Avengers: Endgame, since the announcement of its release had been breaking several box office records globally and with the speed of Flash. Even now, as the latest Marvel Cinematic Universe movie reaches its second weekend of box office domination, the revenue is pouring in like anything.

This must not be surprising for the Marvel fans and entertainment industry pundits as the hit of the movie and breaking of certain records was always predictable, Avengers: Endgame being the last Avengers franchise movie and the marker of the end of the first phase of Marvel Cinematic Universe. Then there was Thanos, "what will happen to Captain America, Iron Man, and snapped Avengers" questions to be answered, and the entry of Captain Marvel in the team of Avengers. The Russo brothers actually left no stone unturned to make sure that Avengers: Endgame becomes this year's (if not ever's) biggest blockbuster globally.

MCU is indeed playing it like it is the Endgame. The entertainment gurus expect the movie to break the records of all the biggest movies ever, namely, Avengers: Infinity War, Star Wars: The Force Awakens, and Titanic.

But there will still be one movie which Avengers: Endgame will not be able to beat, most probably, ever. The movie is, as you pointed out, James Cameron's intergalactic drama, Avatar. The movie which was released in 2009 is the biggest global hit ever. It achieved, even with much less number of screens and ticket prices, what Avengers: Endgame is still way too far to achieve.

The two biggest markets of Avengers: Endgame, America and China, both had a minimal number of screens back in 2009 to play Avatar. The number of screens has increased exponentially since then. Apart from this, the frenzy that Avatar caused created world standards for any movie aspiring to be a global hit.

So even if Avengers: Endgame crossed the net revenue of Avatar, it will do it with the advantages of its age and era and hence will never be really as big a hit as Avatar was in its time.