If you have something that generated 20 lines of assembly that takes 100x times more than the 2 lines of clever instructions you know, you'd have the same stance even if the higher level was easier to use. Then those kind of performance tricks ceases to matter. But reliability still do. And the reasons we use higher and higher level of programming languages is because they increase reliability and simplicity (at the cost of performance, but we're happy to pay those).
LLMs output are unreliable and productivity is still not proven for an end to end engineering cycle.