A programming expert is not a person who has memorized the contents of the programming equivalent of the Oxford Dictionary, but one that can write code the way Hemingway could write books.
You've ignored the other half, the mechanics. The mechanics are not about memorizing volumes of texts, Aspects of an expert include having been there and done that, learned from own or other mistakes. Knows the roadmap, overall rules of the domain. Consider a programmer as a medical practitioner (Doctor). What are the properties of an expert Doctor? Much of what I've briefly stated above: Lots of experience, knows what is most likely (not guaranteed) to succeed or fail given known conditions.
Now imagine you are an expert doctor and the human physiology radically changes every 2-3 years? The field of given known conditions also radically changes. How can you keep up on these changes and all their nuanced inter-relationships?
But the river itself and its flow remains the same.
There's a lot of fuzz all the time but, for example, in the last twenty years what has really changed? The playground has invented itself a few times and we're juggling primitives of a much higher level of abstraction as before. But there are always the set of primitives and, out of them, our job is to create the rest of it, the new things, for we are makers.
Doctors aren't makers of new but practitioners of what's known.
River flow does not stay the same. The rate of flow changes with the seasons and geographically, rivers can move over time, depending on local geological conditions.
Doctors are makers of new, otherwise where do our medical advances come from? They have to explore the unknown to make it known.
Yes, "primitives", our foundations in digital technology and programming fundamentals are the same. We still use collections and algorithms, and our computing technology is still rooted in the core theory of the Turing machine. This knowledge is very important, but it really is still just the foundation which we need to be effective, develop expertise. The tools we use today, the applications and libraries and languages do change rapidly. And that is where the interactions are complex and change all the time.
> The main thing I noticed about the experts I’ve encountered is they are into impressing you with their abilities. They are usually incredibly good, but their need for recognition gets in the way of mastery. Everything they do is an attempt to prove themselves
An expert programmer is a knowledgeable, yet ostentatious programmer. :-)