I think what has gone down is the value of the aforementioned skills. Aside from caching and algos, very few engineers I know at FAANG are using any of these. I

I think what has gone down is the value of the aforementioned skills. Aside from caching and algos, very few engineers I know at FAANG are using any of these. I have a formal CS background, but in the industry these topics have been abstracted away to the point where you don't need to worry about them 99% of the time. If you're building extremely complex or expensive systems, then sure, but most businesses aren't.