Massachusetts Institute of Technology's signature Great Dome is draped with a giant cloth version of Captain America's red, white and blue shield, in Cambridge, Mass., on April 28. (Raymond Huffman/AP)

It was only a matter of time.

As it closed out its second weekend of cinematic domination, “Avengers: Endgame” crossed $2 billion and became the second-highest grossing global film of all time.

Coming off a record-breaking opening weekend, Marvel’s superhero epic kept going strong around the world to land at a total of $2.19 billion, $620 million of which has come from the United States.

That has leapfrogged it over other blockbusters on the global earnings chart: “Avengers: Infinity War” ($2.05 billion), “Star Wars: The Force Awakens,” ($2.07 billion) and “Titanic” ($2.187 billion).

In film, though, these are only the silver medals. The big prize is “Avatar.” James Cameron’s 3-D intergalactic tale of the Na’vi and Pandora is the standard for global blockbusters for the way it dominated theaters at the end of 2009 and the early parts of 2010. Its total is $2.78 billion, a crown no blockbuster (even an MCU blockbuster) can ever seem to take.

Or can it? Since the opening weekend’s startling “Endgame” numbers (including a $357 million sum in the United States), pundits have begun asking the kind of question that seldom gets asked — whether the previously unobtainable is possible. As this article put it, “Can ‘Avengers: Endgame’ Topple ‘Avatar’s’ $2.8 Billion All-Time Record?"

The talk of the film crossing that threshold is far more intriguing — and complicated.

There are certainly pathways for it to get there. The United States will be key to that effort. The movie already got a boost from a big second weekend of $146 million, a respectable 55 percent drop from the first weekend (60 percent is mediocre, 50 percent is really good). That could help power it to an additional $300 million in the United States, atop the more than half a billion it’s already grossed, and get it within sniffing distance of the blue creatures.

“Endgame” will also need to have staying power in China, the world’s second-largest theatrical market by dollars and one that has been essential to its smashdom to date.

In fact, China is responsible for $576 million of the box office in its own right. (No other foreign country has yet to hit $100 million. Incidentally, the “fastest to $2 billion” headlines you might have read are a little misleading — global simultaneous release is a recent phenomenon. Other mega-blockbusters took longer to hit that mark in part because they rolled out more slowly; even “Star Wars: The Force Awakens,” three years ago, didn’t open in China until three weeks after the United States.)

But here’s why even if “Endgame” gets to $2.78 billion, it will never really be bigger than “Avatar.”

The most obvious reason is inflation. Movie tickets cost a lot more now than they did in 2009 — a full 20 percent more in the United States alone. That means “Avatar” would have grossed $150 million more here than its $760 million domestic total in today’s dollars, a number that puts “Avatar’s” global total near the 3-billion-dollar mark.

Of course a lot of “Avatar” tickets came in 3-D, which cost a lot more to begin with. So the idea that “Endgame” isn't matching “Avatar’s” popularity because movie tickets cost more in 2019 isn’t exactly accurate.

But here’s why it really shouldn’t be considered a bigger hit. If you play on fewer screens, you’ll take in less money. And “Avatar” was playing on fewer screens than “Endgame.” A lot fewer screens.

And the biggest country in which that was the case? China.

Yes, the Middle Kingdom has been responsible for $576 million of “Endgame” box office so far, nearly triple the $204 million “Avatar” took in there. But the Marvel movie has a major advantage in China that “Avatar” didn’t have when it came out — the country has been blanketed with movie theaters in the past decade. In fact, there are entire towns and cities that couldn’t play the Cameron-fest but can now play “Endgame.”

Back then, the country as a whole had just under 5,000 screens. Wanna guess how many it has now?

No, it’s higher than that.

Nope. Still higher.

There are now an estimated 60,000 movie screens in China. (The United States has 41,000.)

This makes for an astonishing figure — for “Avatar.” That movie managed to take in more than a third as much as “Endgame” in China, despite theater capacity that wasn’t even a 10th of what it is now.

Even if “Endgame” continues to rake in the coin in China, garnering as much as four times as “Avatar,” it still shouldn’t be equated with the Cameron blockbuster for this reason: It’s had more than 10 times the screens on which to play.

(Incidentally, this is also true, to a lesser degree, in the United States. “Avatar” was on at most 3,460 screens, 30 percent fewer than the 4,660 screens “Endgame” has been on.)

So, yes, even if “Endgame” surpasses the $2.78 billion mark with a colossal, massive and generally adjective-defying global performance, it will, as far as movie-popularity rankings are concerned, always be No. 2.

Of course that hasn’t stopped some pundits from preparing for a global showdown involving the MCU movie. If it does cross that number, some have asked whether “Endgame” can be dethroned for another reason.

As this pundit put it, “Is ‘Avatar 2’ The Film To Break Avengers Endgame’s Box Office Record?”

This post has been updated.