At the time of writing, Marvel Studios hasn’t revealed the reason behind the cancelation of the Assembled series’. The studio might have canceled it as a measure to cut costs and reduce projects.

Back in 2021, Marvel Cinematic Universe fans were introduced to "Marvel Studios: Assembled." The docuseries covers the making of the various MCU movies and shows, starting with Phase Four.

“Assembled is a comprehensive series of documentary-style specials streaming on Disney+ that chronicles the creation of Marvel Studios’ thrilling new shows and theatrical releases,” reads ...

Marvel Studios' Phase Five Movies And TV Shows Ranked From Worst To Best (Part 2, #7 - #1) "You should be able to watch these shows on their own, without knowing the overall MCU story," he added.