When you have a Dungeons and Dragons movie hitting over 100mil in the box office, and when comic book movies are some of the highest grossing, i think its pretty safe to say nerd culture is incredibly mainstream.
There were popular D&D shows already in the 80s.
Most comic book movies are simply bad, and "real" nerds hate them.
No nerd loved the last Star Wars trilogy or Rings of power or Wonder Woman 1984 or the nth spider-verse repetition, mostly because studios take something popular among nerds and change it to please modern audience which is exactly what's wrong with the so called "nerd culture" today: it's not a culture.