there’s a cliff of unknown unknowns that is basically bottomless and is known only to people who grew up with the incremental changes.
Don't give this stuff any more reverence than it deserves (which is none). Bob Barton [1] once said "Systems programmers are high priests of a low art."
You don't need to know all the incremental changes, unless the allure of becoming a historian and being able to recount all the developments in the space appeals to you. (Those who do not learn from history are condemned to repeat it.)
There is no mystery except the one you make for yourself. Read books. https://man7.org/tlpi/ is a good place to start. Good luck!