> Perf teams on operating systems do things for systemwide performance with small percentage wins all the time.

And they evidently spend very little time on the things that would actually improve the lives of their users in macroscopic ways. The fact that our dominant model of an operating system is essentially c + shell is a tragedy. The operating system does almost nothing for us to help write fast, correct programs in a reasonable amount of time. It is of course for this reason that unix itself has barely improved in a material way in 30 years except in these kinds of microbenchmarks. Third party tooling and languages have of course improved, but largely to cover the gaps that the operating system has largely failed to address in a meaningful way.