The problem is that even amongst "serious" programmers people often have a patchwork of knowledge with small, unpredictable gaps in understanding; many of which will surprise you. You will find these gaps even if you've taken the time to handpick vetted experts. Once you account for this patchwork of knowledge gaps in verified experts you'll often notice that you're really close to a tutorial for relative beginners, which most people are, and just go the full distance.
The problem generalizes to a variety of subjects but is particularly pernicious in programming where small details are often of much greater significance.
And that problem only becomes worse the further you get into these topics.
When you add to that the fact that anything specialized will become outdated very quickly, incentives are not aligned for there to be a lot of deep, insightful articles about anything.
There just aren't enough people who would be interested in it to make it worth the time someone would take to create it.
edit: And of course, StackOverflow is a great place to find these types of things because it serves as a watering hole for the types of questions and discussions it sounds like you would be interested in.
Too much of programming education / online stuff is muddled with millions of media items that cater to absolute beginners.
I rarely come across deep, insightful articles that discuss at-least one level beyond the standard stuff. Any search for any programming related question leads to articles that start from installing Node / Python.
Stackoverflow is an exception though.