That’s a disingenuous misinterpretation of what “zero-cost” means. Zero-cost refers to runtime performance of compiled code. It’s also disingenuous to pretend

That’s a disingenuous misinterpretation of what “zero-cost” means. Zero-cost refers to runtime performance of compiled code. It’s also disingenuous to pretend there isn’t some downside to not using the abstraction. Obviously you need to evaluate the tradeoffs. High level code itself is a sort of abstraction. We could write raw assembly all the time to remove that abstraction and associated costs, but clearly that’s not very productive.