Haha "death by a thousand cuts" is exactly the phrase I encounter in these debates! And actually I still disagree - e.g. I once took over a DMA management firm

Haha "death by a thousand cuts" is exactly the phrase I encounter in these debates! And actually I still disagree - e.g. I once took over a DMA management firmware and the TL told me "we are really trying to avoid DBATC so we take care to write every line efficiently". But the thing was that once you have a holistic understanding of the systems performance you tend to find _only a small fraction of the code ever affects the metrics you care about_! E.g. in that case the CPU was so rarely the bottleneck that it really didn't matter, we could have rewritten half the code in Python (if we'd had the memory) without hurting latency or throughput. Admittedly I can see how games or like JS engines might be a kinda special case here, where the OVERALL compute bandwidth begins to become a concern (almost like an HPC system) and maybe then every line really does count.