Because Morons, IM3's home entertainment sales were piss poor next to its massive box office. That sends a message to the studio. Which is probably why they didn't keep Shane Black on for Avengers, despite the "box office" telling them they should.
Only Backsdown112 and CPTroll would defend a pile of crap like IM3 over a masterpiece like Civil War 😂
And LMAO at attacking Star Wars but defending IM3