Fox has its own hot Marvel-character franchise with Deadpool, but next month's sequel has been tracking for an opening in the neighbourhood of US$150 million.
And come July, Disney/Marvel's third movie of the year, Ant-Man and the Wasp, would do remarkably well to even open close to Deadpool 2 numbers. (For comparison's sake: Deadpool opened to US$132.4m in 2016; Ant-Man opened to US$57.2m in 2015.)
The only non-Disney/Marvel movie to open north of US$200m is Universal's Jurassic World (US$208.8m) three years ago, so the next true challenger to Infinity War stands to be Jurassic World: Fallen Kingdom in June - yet even amid brimming summer business, most everything would have to break perfectly for Fallen Kingdom to sniff a quarter-billion-dollar debut.
Plus, it will have competition from such franchise films as Pixar's The Incredibles 2 and Warner Bros' Ocean's 8.
Paramount will trot out its blockbuster Mission: Impossible - Fallout in July, and Warner Bros' Crazy Rich Asians could do well for a comedy in August. But after that, nothing looks to have true potential to surprise in a major way till December's Aquaman and Mary Poppins Returns - yet neither of those appears likely to get close to even US$200 million in their debuts.
The next true contenders, it seems, all belong to Disney: Captain Marvel and live-action Dumbo next March, followed by Infinity Wars biggest threat: itself.
The next Avengers sequel, currently untitled, opens May 3, 2019.
And if the second part of this Avengers arc can't beat the first part, then the US$250 million mark could well stand as next year's Spider-Man, Wonder Woman, Toy Story and Frozen sequels, the next Star Wars episode, a live-action Lion King and a Fast & Furious spin-off go whizzing by.
In that case: Enjoy your reign, Avengers, till at least 2020.