It has been a sentiment that is posted on here just about monthly, and this is surely not the first time you've seen it. Usually it yields a lot of cynical posts with clever new phrases for whatever is new, as if there are a lot of people feeling really defensive for whatever they're using.
HN is about the interesting parts of tech, pushing at the edges. Yet the vast majority of developers are developing vanilla IT processes in shops where they want it to be the most benign, easily transferable solution possible. The differential between the two isn't surprising or particularly interesting. It's an obvious outcome.
And in ten years the stuff that people talked about on HN become the normal stuff at those IT shops, and HN will be onto something else. And on your "legacy" shops you'll be using frameworks that incorporated the best of those ShinyNewThings. Or do people really think the Java ecosystem today (or the .NET ecosystem, etc) hasn't changed over that time.
And that's okay. It's okay to wait until it matured. What isn't okay is that it's usually coached in derisive, defensive terminology that denigrates whatever is "Trendy". That part isn't cool