It is and has always been immensely helpful to understand what you are doing in any context.
There are some programmers who treat the job as just plumbing together what is to them completely incomprehensible black boxes, who treat the computer as a mystery machine that just does things "somehow", but these programmers will almost always be hacks that spend their entire career producing mediocre code.
There are things such a programmer can build, but they are very limited by their lack of in depth understanding, and it is only a tiny fraction of what a more competent programmer can put together.
To get beyond being a hack, you need to understand the entire stack, including the code that you didn't write, including both libraries, frameworks and the OS, and including the hardware, the networking layers, and so forth. You don't have to be an expert at these things by any means, but you do need to understand them and be comfortable treating them as transparent boxes that you may have to go in and fiddle with at some point to get where you need to go. Sometimes you need to vendor a dependency and change it. Sometimes you need to drop it entirely and replace it with something more fit for purpose you built yourself.
