Speaking as somebody who never stopped optimizing like its the 90s: there's definitely a learning curve, but when microbenchmarking becomes a reflex, you learn your language in depth and the burden drops quickly. It only seems esoteric to you because the industry has collectively decided that Grace Hopper is an old codger who doesn't need to be listened to.

https://www.youtube.com/watch?v=9eyFDBPk4Yw