In the film, after Stephen Strange is given a brutal play-by-play about how his doppelganger wreaked a royal mess in this particular universe, the Illuminati’s epic annihilation against him is cut short when the Scarlet Witch (Elizabeth Olsen) breaks through company premises. While the audience is still trying to process seeing Jim Halpert seated with Professor X, their dreams quickly turn into nightmares when Wanda single-handedly defeats the Illuminati. These Marvel legends are sliced through in a way that Invincible’s Omni-Man would be impressed with, and in the pivotal scene, Krasinski’s long-awaited debut ends with him being shredded into human string cheese.
Since this isn’t the “primary” MCU Reed, logically Krasinski still has the door wide open to star in the upcoming Fantastic Four reboot. However, for exactly the same reason, the door is in addition wide open for another actor to fill that role.
In fact, it’s entirely possible if not probablythat Reed’s debut here is a way for Marvel Studios to have both: if Krasinski’s Reed is a hit with viewers and he’s interested, they can cast him wholeheartedly in Fantastic Four, but if not, they can just as easily occupy someone else. This fits in with Joe Russo’s previous description (as of Deadline) that Marvel’s “big plan” is a looser idea than most people think, with plenty of room to tinker with the details based on fan reactions. Nonetheless, after such an unequivocal on-screen character execution, one wonders what this Reed’s arrival and swift departure could mean for the future of the Fantastic Four… and whether a past, poorly received decision by the studio could be being repeated.