Web Devs Aren’t Learning the Basics. Does That Matter?
futurehosting.com
futurehosting.com
So people have to be selective with what they learn based on how far it will take them. And a solid understanding of tools that aren't CSS / HTML gets you pretty far these days.
Entry-level... easily the case can be made that if you want to get a website up, just hit the button at Digital Ocean to create your Ghost Blog, then grab a theme somewhere, and change the colors and go. (Wait... is any development knowledge even really needed any more?)
But for career advancement, and supporting legacy systems, and building things from scratch... yes, you need to have a good understanding of ALL the pieces -- or your team does at any rate. And, if you go the team route, you also need a good Product Manager to make sure all the people are connected and aligned.