Ya totally - those wacky people at chrome must've just never heard of those headers /s

What you don't understand, because you don't work on Chrome, or Chrome sized projects, is that generic, lowest common denominator implementations cannot be optimal for all use-cases and at scale (Chrome-sized project) those inefficiencies matter. That's why this exists, that's why folly exists, that's why abseil exists, that's why no not everyone can just use boost, etc etc etc