No it's not. "Pop culture" (or "mainstream"-ness) must reach even "a member of the elite class", to be pop culture. The point at which something becomes "pop culture", is precisely the point at which it becomes equally likely that you've heard of it, no matter which demographics you're a part of. If there's even one demographic (like busy rich old white men) that can still be completely isolated from a thing's "reach", then that thing is not pop culture yet.

If all 20-year-olds know about something, but all 40-year-olds do not know about that thing, then that thing is not "pop culture" (or "mainstream", either-or.)

On the other hand, if 10% of ten-year-old boys and eighty-year-old women and plumbers and astrophysicists and farmers and investment bankers have all heard of the thing, then it is "pop culture."

Try that criterion out. It really does work:

• Beanie Babies? Pop culture.

• Pogs? Not really pop culture. They were a fad, but they died out before they reached universal intelligibility.

• The movie Titanic? Pop culture.

• The movie The Matrix? Not quite pop culture. My grandma hasn't seen it. Yours probably hasn't either.

• Pokemon in general? Not pop culture.

• Pikachu in particular? Pop culture. (Thus the recent movie.)

• Snoopy? Pop culture. Americana, even. ("Americana" being a word meaning "pop culture, but pretty much only in America, so we've latched onto it as a thing that reminds us of America.")

• Hello Kitty? Pop culture elsewhere, but not-so-much in America, despite what certain stylists like to think.

It is by this same criteria that I claim that "video games up to 2003" were not—as an abstract gestalt—part of pop culture, and that "video games starting in 2004"—as an abstract gestalt—were part of pop culture. They went from being "Hello Kitty" to being "Snoopy"; from being "The Matrix" to being "Titanic"; from being "Pogs" to being "Beanie Babies."