At the same time, it seems like in some circles Dublin Core is what got metadata standardization started. I encountered it as an older format in the mid-2010s

At the same time, it seems like in some circles Dublin Core is what got metadata standardization started. I encountered it as an older format in the mid-2010s when working on data discoverability for geospatial datasets. At the time, we were emitting Dublin Core as one format for our datasets in the archive. We were actively transitioning to supporting a more fully featured FGDC format as well as diving into the ISO 19115 standard and translating to that. In all, I think Dublin Core was, at one point, useful. However, metadata standards have moved forward with more specialized schemas that are more useful for discoverability.