My belief is that it takes a certain isolated 'incubation period' for 'culture' to form; i.e things like small cohesive local scenes, specialized clubs, artists beating their own paths, taking a certain very specific set of ideas (many times because they don't have exposure to other ideas) and refining them continuously... Having read a number of artist biographies and 'history of the scene' type writing, I get the impression that there's usually a phase of 'nobody is watching except this small and very specific audience' at which point certain unique tropes are defined and refined without much pressure or self-awareness on the artists' part. Think about how many previous scenes can be strongly tied to a specific city or even venue. CBGB for punk, The BatCave for Goth, washington DC for hardcore music, Seattle for grunge; no one from outside was paying attention to these scenes until they developed a very specific, intriguing culture, and then spread globally.
Nowadays there is the built in expectation, right from the beginning, that whatever work you produce might reach an audience of unspecified millions. In practice this doesn't usually happen, but the promise weighs heavy on artists minds, and I think leads them to play along with tropes that most consumers would find already familiar or comforting. That is, rehashing already established styles and re-iterating already popular tropes. As a small example, think about how a typical comment section on youtube is just people making variations on the same already expected joke over and over, trying to seek approval. Imagine if, for whatever reason, you could only read comments from people who live in your general area. There would, at the very least, be a few things like area specific in-jokes, that varied from place to place.
I was reading a book called 'Filterworld', about the influence of social media algorithms, and there was a very intriguing section about how a number of very similar, 'instagrammable' coffee shops were appearing all over the world, ready-made for trendy social media posts. None of them were founded by the same person, or had any relation to each other. These coffee shops were not influenced by the local culture of their countries, they were influenced by the potential of striking it big on a generic globalized cultural stage, and as a result they turned out much the same, everything from the light fixtures to the paintjob pushing the expected buttons.