I would say most of the examples in TFA are deployment diagrams, not (software) component diagrams. For all the flaws of UML, at least it taught us to be quite specific in which aspect of the system we are currently modelling.
Lately I've been trying to work my way through lots of different diagram types from https://plantuml.com/, and it does help to wrap my mind around the existing options.
Unless teams are bound by some ISO to have design documentation timestamped earlier than feature DoD, engineering process gets flipped on its head and design docs are quite likely to be simply braindumps of some uninterested party rather than formal-ish specifications driving the implementation.
> when we have plenty of mature tools and established best practices that people don't care to learn.
Hyper-fixation on agile and "move fast and break things" attitude is in part to blame here. You can't really put a timebox on "learn how to use mature tooling" or storypoint "design architecture", when only implementation is rewarded.