This question has been a bit hard for me to unpack, but I’ll do my best to give a comprehensive answer.
If the MC’s approach is the wrong one, and the IC Changes, then the story will end in Failure. (I think some Greek plays may violate this, but they employ a Deus ex Machina. I don’t have an example.) If they remain certain that their way was correct, even as the story ends in Failure then they must be blinded somehow. Or crazy. Maybe the ending of Sunset Blvd. is relevant here.
Perhaps what you want to do is having the MC actually be correct and lead the story to a Success but have an insanely high Cost. To quote King Pyrrhus: “Another such victory, and we are lost.” This might make the audience feel complicit because they cheered for the victory but didn’t consider the price they’ve have to pay.
Another possibility would be to have the Main Character be the Protagonist, but abandon his plans at the end, only to have a different character follow through. A similar (but not identical) thing takes place in Lord of the Flies, where [SPOILER – worth an unadulterated read if you haven’t read it] the Protagonist abandons his plan only to have the Antagonist follow through.
Hope that helps.