This article misunderstands what a "culture" is. Specific activities do not constitute a culture. Niche interests within a single domain do not constitute a culture. "Interest in Marvel movies" or some other figment of pop culture is not itself a culture, not by a long shot. This is why we can speak of a "pop culture" in the first place, because we sense that many things - nominally unrelated products situated within different domains though they may be - are all related in some important way, contained within a broader popular culture that transcends any of its manifestations. Perhaps the defining mark of popular culture is that the people who consume it and participate in it tend to overlap, or resemble one another. This way of thinking means that cultures are defined more by their participants than anything else.
Culture is broad, it is cohesive, and it extends and influences across many domains. There are absolutely countercultures out there, but most people aren't aware of them given how dominant the dominant culture is, which is generally the case but especially true today.
"Counterculture" is a very US- and Anglo-centric term to begin with. It implies that there is a "mainstream" culture to be opposed. In this view there are nerds with eyeglasses and specific interests and normies with a better chance of reproduction. The mainstream culture is the post-WW2 consumer culture that grew around commercial TV shows, blockbuster movies and advertising and household consumption through items like washing machines and vacuum cleaners.
Today, YouTube and TikTok are channels which multiply and amplify this kind of culture worldwide.
Culture and Counterculture have always existed. What you're describing is just the most recent instance of the Culture/Counterculture dichotomy. That doesn't mean the entire concept is inapplicable to other places or times.
Culture is broad, it is cohesive, and it extends and influences across many domains. There are absolutely countercultures out there, but most people aren't aware of them given how dominant the dominant culture is, which is generally the case but especially true today.