Was this real? Did I mandela effect it from the negative zone or something? Am I just getting old?

I think so. I don't think Scott Pilgrim had anywhere near the cultural impact you're assigning to it. This is my anecdotal memory, so take it for what it is.

When it came out, it did well, people talked about it for like a week or two, and then everyone moved on to whatever the next movie was, like most popular movies. It didn't have even half the cultural impact of Fight Club, people weren't still quoting it years after it came out, I had honestly forgotten about it till everyone here started talking about it again. Even among the bigger fans of the movie I've met, none of them emulated Scott, consensus seemed to be he was a douche. Even I got that when I first saw it and I sucked at media analysis back then. They cast fucking Micheal Cera to play him, people have hated that dweeb since he was in Arrested Development, he mostly gets cast as annoying assholes these days.

I think the movie got made because annoying hipsters were a thing at the time it came out, there were already tons of memes about how annoying hipsters were, years before the film was even in Pre-production. I don't think the film made any significant contribution to the population of hipsters. I was a bit of a hipster back then, and I liked the movie but it didn't inspire me to be more of a hipster, if anything it made me wanna cool it a bit.

So I don't know why everyone is assigning all this cultural capital to a movie that was about as influential as Weekend at Bernie's.