Sheesh. Can something this complicated ever truly be said to work?
I suppose someplace someone is running an embedded system without an OS on such a processor - but I'd expect they are still using extra cores and so have all of the above tricks someplace.
Yes it matters on MS-DOS like OS design, like some embedded deployments and that is about it.
It is even impossible to guarantee a process doesn't get rescheduled into another CPU with the performance impact it entails, unless the process explicitly sets its CPU affinity.
The way it is measured, is mostly ideal, assuming that threads run to completion without any of those side effects taking place.
Turns out the first scenario is rare outside of embedded or OS development. The second scenario defeats the purpose because you're doing the same thing a mutex would be doing. It's not like mutexes were made slow on purpose to bully people. They're actually pretty fast.
It's a weak signal but the reasoning is sound.
Code has a minimum complexity to solve the problem
You may have some simple chemical life needs, and life may have some other simple chemical it can use to get the needed simple chemical, but the processing steps are complex and limited by physics themselves. Evolution almost always finds a path of using the minimum activation energy to let these reactions occur. Trying to make the process simpler just doesn't get you what you need.
Everyone's computers hang or get slow some of the time. Probably all of our locks have bugs in them, but good luck getting to the bottom of that, right now the industry is barely capable of picking a sorting algorithm that actually works.