You didn't ask me, but IMHO, I think it's just bad timing (post-pandemic and the MCU feeling played out to a lot of "civilians") and the fact that the new FF movie was preceded by three mediocre film adaptations.

Coming out after Superman didn’t help, and a lot of people don’t know that this was made by Disney and not Fox.

I know Marvel retreated from Kang, but I think they really should have pushed forward with Young Avengers
even if they had to dump Iron Lad or quickly base him on some other character. They had done a good job
establishing Kate Bishop, America Chavez, Wanda's two children, kind of, and Ant-Girl/Stinger/Stature. Even
if their Secret Wars series bombed, they still could have grabbed a Hulkling skrull.

Then give those kids a chance with a fun movie with a low stakes (not a Save the Universe Epic) mission. Establish
the characters (as if no one in the audience had ever seen them before). The Ms. Marvel series proved popular
enough, so Kamala Khan could have taken Iron Lad's spot. A good balance of young women and men, 3 each.

But, as it is now, some of those actors are already getting old. The last Cassie Lang actress is already 28. You
kind of need these actors to look like kids and teens for two or three movies. And, if needed, a Dr. Strange and
an Ant-Man, and a Wanda cameo could have helped sell it as being part of the Marvel Universe.

If not a movie, Disney should have pounced on it for a Disney+ series. Maybe retooled it as Avengers Academy.

This is where the reality of contracts and actors aging comes into play unfortunately. People want Downey, Evans, and so on (this is why IMO recasting wouldn't have worked to just keep going with the films).

Yeah, I wasn't interested in getting typecast forever..

All 13 episodes of the 1975 FF radio series.