They briefly mention literature and I think that provides a good counterexample. Books are highly individual, and always have been long before streaming existing. Yet, there still manage to be runaway hits that everyone reads and talks about. The same could be true of streaming shows. Stranger Things managed it in the streaming era.
But at least for now, streaming shows are inherently silo'd. You must have a subscription at some particular service, and there aren't any real "meta-service" bundles either which makes it fragmented even compared to something like cable. They're ephemeral, harder to trade around, etc. It's a significant amount of friction vs a book isn't it? If there is buzz and word of mouth about a book, anybody can simply go and get a copy for the one-time outlay of that copy, or borrow one from a friend/family, or for that matter go to the library (we have an entire public service dedicated to free availability!). But if someone tells me about a great show they watched on a service I don't subscribe too, well, it's probably not going to be enough to get me to sign on. I'm feeling pretty sub'd out. Maybe I'll go check a torrent site or something, but maybe not. I can't just tune in on that channel and check it out, or duck into a book store and read the first chapter then grab it or not.
Books (and other low capex media in other countries for that matter) do show that huge culture-wide hits can emerge organically from enormous diversity and niche. But I wonder if the higher the technological barrier to entry the harder that is. It might be hard for it to happen without more cooperation between services, meta-services, a reemergence of some utterly dominating service/monopoly, or a legal imperative for interoperability or cross licensing after a delay.