Those last posts quite neatly cover the usual spread of acquiring knowledge - books & printed research across a topic; specific research for a project; learning in the course of your job; hobbying/geekdom; & sort-of-osmosis.
That takes you through 'high-concentration & application' at one end of the scale (The Animus' textbooks) through to 'enjoying what you do & barely class it as study' at the other (the soaps & football analogy). That is the side of things that always bugs teachers of course; why can't you memorize Henry VIII's wives the same as football trivia. It is simply easier to retain that stuff because as well as being interested it kind of just 'goes in' eg you don't actually learn & revise song lyrics, Eastenders, etc etc. And it usually stays in, too, unlike learned facts & figures. (Not that that is a new observation of course).
Interesting to me to see how it applies in this specific field, as I would not really know without asking which of these is more applicable to in-depth tech knowledge - ie is it nearer to nuts & bolts study & learning your subject, or more towards soaking it up as you go. Or whether that very much depends on the individual.
I can appreciate that, as I touched on in my last post - as well as there being a huge amount to take in in the field of tech, it has this enormous turnover of specifics. If you lock a tech expert in a cupboard for a year* then he will retain most/all of his bare bones knowledge, ie he will still know what a gpu is, but that will be in quite a contrast to the fact he may now be significantly out of touch with current gpu brands & specs. Whereas an astronomer for example will find most/all of his knowledge is still valid & will only have to catch up on any new data rather than ditch & replace a good deal of what he knew previously. I imagine. So you are all giving yourself a pretty high workload just to keep up, & also make sure you don't become blinkered & closed off to new developments, as you say. Again, nothing you don't all know, just thinking aloud.
*the hexite of your choice, let's say