When people describe geek culture as now being “mainstream” because certain evergreen science fiction and fantasy properties make gobs of cash at the box office and are marketed to every new generation...I disagree.
Fretting over whether something is mainstream or not isn’t the issue: I don’t care if geekdom is mainstream or not. But I still see a partial division between the popularity of genre entertainment, and the “geek culture”.
It’s because of one of the ways people are geeks. It’s not the only way to be a geek, certainly not the “right” way to be a geek, but it’s a way. A distinct way of dealing with media.
Some geeks, you see, they dig deeper. They engage with media that the culture at large has forgotten. They fall in love with minor characters (literally or not). They pick apart every tiny little detail, and then dig up more.
Not every geek does this, but enough do that I feel like, even if Star Wars and Spider-Man are explosively popular, there are these practices common to “geek culture” that the public as a whole doesn’t engage in, and therefore it’s not accurate to say the entire thing has gone mainstream just because certain things geeks like have become popular.