If you find yourself wondering this, the answers are in an undergraduate economics course. Please learn the basics ;)
Certainly not because the developer didn't learn all the x86 machine code mnemonics by heart.
How is that relevant? A computer architecture class explains the high-level concepts of an ISA and micro-architecture, covering features from across the domain.
There is never a strong focus on x86, and any kind of rote memorization has nothing to do in a higher education institution.
Are you autistic or something? Serious question. You seem to have a hard time understanding other perspectives, and you missed obvious sarcasm/hyperbole there.
Because the developers are not using Chrome tools to profile their web apps, and they are not collecting performance metrics in production?