So, it was initially uh... perhaps, outsized in its popularity, more popular than it should have been?

...because it actually captured, pretty accurately, the basically underground video game nerd culture of the time.

Up to that point in time, gamers, now basically a dirty word, but back then, it was... a whole bunch of mostly socially awkward and mostly socially ostracized nerds who had their whole own set of lingo and memes and references that... nobody had ever really portrayed genuinely, accurately, in a movie before... and basically all movie adaptations of video games were horrendously bad.

Like absolutely yes the film and plot have not aged well... but a lot of that is because what was once a very niche, not publically acknowledged culture... is just now pervasive everywhere... basically everyone plays video games now?

whereas a few years before the movie came out, you had jack thompson going on a very public crusade to just try to ban every video game he could, half of america doing moral panics over various video games.

Scott Pilgrim coming out as a movie arguably represented roughlt the turning point at which video gaming as a culture/hobby became, or rapidly began to become, much more broadly accepted and embraced by society at large, without just constantly shunning and mocking them for it.

I dunno, thats my 'thesis' there, could be wrong.

Maybe... maybe you could use something like total PAX attendance by year as a rough numerical backing for this?

Back before the movie came out... PAX only had one location, one event per year, and the lines were not stupendously long. Now it has what, 3, 4 locations per year, and the lines are godawful.