While this is true, I can still code circles around frontend developers using vanilla JS.
The decline of jQuery is mostly due to the rise of webapp frameworks like React and Vue. But if you are tasked with adding like, a button to a static webpage, jQuery is still the king.
Only thing I always have to look up is how to make sure my script is executed once everything is done and not before and "ready()" is obviously easier than adding an event listener to "DOMContentLoaded". Yeah, had to look it up for the comment.
$(thing).doThis() is just so perfectly terse and understandable for what it's doing. Not just writing, I find jQuery to be very, very easy to understand and read.
Partly. Frameworks like Angular/React/Vue are a necessary byproduct of building and maintaining large codebases. But the fall of jQuery was largely a result of a more standards approach in mainstream browsers (said another way: deprecation of IE and not needing to work at maintaining consistent behavior across browsers), as well as adding traditional jQuery-like features to vanilla JS.
There really isn't a big use-case for jQuery anymore, although I will remember it fondly.
My first use of jQuery was in the dark days was building UIs (with things like drag and drop, etc) that had to run on Internet Explorer and Netscape. We'd started with "vanilla" but were ending up with what was effectively two separate codebases. Moving over to jQuery let us eliminate a massive amount of duplicate code and dramatically increased our productivity.