You could have said that 20 years ago. I've never needed to worry about clock cycles or cache locality, I don't even know how to measure cache misses in my cod

You could have said that 20 years ago. I've never needed to worry about clock cycles or cache locality, I don't even know how to measure cache misses in my code (I have a CS degree too). And the most consideration I give to memory consumption is whether to process data in a stream, or in memory. It's absolutely the case that some developer still need to care about those things, but by the time I started my career 20+ years ago, it was possible to make a good career as a dev who didn't know how to work with computers at an extremely low level.